Guest Double M Posted August 4, 2011 Share Posted August 4, 2011 So, is there a solution for Code 21?:confused:It indicates a main brake valve failure, but there is no part number for a "main brake valve" in the NAPA system. They dont even know what he is talking about. :eek:Is this "part" integrated into some other part that can be replaced?Am I the first to encounter a Code 21?There has to be some solution prescribed for this fault code...The solution presenting itself at the moment is to rip the @#$%! thing out.:mad:Thanx in advance for letting me pick your brains a little further on this. The car seems to be stopping fine and it has been given a complete Brake Flush. My mechanic said the Brake fluid was contiminated and looked "real ugly". Link to comment Share on other sites More sharing options...
Guest dpannell Posted August 4, 2011 Share Posted August 4, 2011 Did your mechanic clear the codes after performing the work? Does he have a factory service manual?....I'd really recommend owning a factory manual on any car > 10 years old, they can save alot of frustration, time and money. Dave Link to comment Share on other sites More sharing options...
Jim Posted August 4, 2011 Share Posted August 4, 2011 So, is there a solution for Code 21?:confused:It indicates a main brake valve failure, but there is no part number for a "main brake valve" in the NAPA system. They dont even know what he is talking about. :eek:I have about 15 running vehicles that I maintain and am very proud to state I have not spent one penny in a Napa store in the last several years. I refuse to shop at Home Depot either. The connection----------they both sponsor Toyletotas in Nascar.OK, off my soap box. The main valve is part of the valve body block on the side of the master cylinder. The valves are not replaceable individually but you need to either find a good used valve body somewhere or replace the whole ABS unit on the firewall. I do have a good complete unit available but not just a valve body. Link to comment Share on other sites More sharing options...
Guest Double M Posted August 4, 2011 Share Posted August 4, 2011 "replace the whole ABS unit on the firewall"Does this "whole ABS unit" have a part number? Is it something that is available anywhere other than junk yards, including non NAPA stores? Is this something that we may be seeing more of as time goes by?You do good on your soap box! Link to comment Share on other sites More sharing options...
DAVES89 Posted August 4, 2011 Share Posted August 4, 2011 There is a specific sequence of tests that must be run, and it does call for the use of a "break out" box #J-35592 [starting with testing resistance of pins 11&18]. I am not sure how your mechanic is testing without this box, but good for him to figure something out. I have also gone back to the u-pick yard and cut off all the pigtails that connect to the Teves master cylinder for future ease of testing. Anyway I bought this box about 2 years ago when I had a problem with my ABS light. [Turned out to be bad sensor leads]. Cost me about $50-60.00 on Ebay, I consider it invauable. I am also running code "21" which from the tests I ran, indicate a bad ground. I have had no braking or "red" brake light issues. I am leaving my situation for my mechanic friend to confirm and repair which will be on Monday 8/9. About 2 years ago, I pulled a ABS valve body off a Cadillac to have inventory. I put it in a resealable plastic bag, and set it on my shelf. I could not test it as the car was not running. I DO NOT KNOW IF IT IS GOOD. However here is the deal, If it turns out that I do not need the ABS valve body that I took off this Cadillac, you can have it for the cost of freight [$15.00] as I am no longer interested in keeping this kind of inventory around. Link to comment Share on other sites More sharing options...
Jim Posted August 4, 2011 Share Posted August 4, 2011 There might be a part number for the whole unit but it would be really expensive from GM and regular auto parts stores would not have the complete system.I think Prior in Texas is still rebuilding these Teves units but believe the price is up to about $ 750.When I get in a parts car I take the car out on the road and to a brake test to make sure the unit is working correctly. One of the tests I do is to get the car up to about 20 MPH and then do a panic stop. If the car stops straight ahead and does not have a hard pedal the unit is probably good. This tells me all the valves in the valve body are working as they should.Many years ago it was figured out that it is VERY important to change the brake fluid about every five years. The reason is brake fluid naturally attracts moisture and this moisture will corrode the valves in the valve body. On many occasions there will be no indications of a problem until you have to make a panic stop and then it might be too late.About a year ago my wife's car was pulling to the left on sort of hard stops so I changed just the valve body and now everything is correct.It is not real easy to change the valve body as you have to remove the pump and motor to get at the lines on the bottom of the valve body. The body is on long studs and then the EGR valve gets in the way.Very often I see complete units in junk yards but do not buy them because if I cannot road test the unit I will not sell one.I don't guess we will be seeing any more or less of this in the future as because the cars are over 20 years old the problem has been around for about 15 years. The key is CHANGE YOUR BRAKE FLUID ABOUT EVERY 5 YEARS. Link to comment Share on other sites More sharing options...
wws944 Posted August 4, 2011 Share Posted August 4, 2011 On many vehicles with ABS, one is supposed to use a scan tool to command the ABS valves open while bleeding the old fluid. This prevents air pockets from forming. And an air pocket is exactly what one does NOT want when the ABS kicks in during a panic stop.In the case of our Teves system, is there a similar special procedure? It seems to me that a 'pedal to the floor' might indicate that an improper bleeding procedure was used at some point in the past...And yeah - brake fluid should be replaced every now and then. Interestingly, GM has no service recommendation on this. I have even had a dealer service writer tell me it is 'good for the life of the car'... Some mechanics recommend every two years, and serious racers/autocrossers do it even more frequently. However Jims recommendation of five years is probably a decent one for most people.This comes back to something I have said before: a good rule of thumb for buying any used car is to reserve about 10% of what the car cost *new* to fix up all the stuff the PO messed up or ignored. Adjust from there based on age and neglect factor. (E.g., a three year old 'cream puff' with full service records will likely need less work than a 20 year old car that has been trashed by a series of teenage drivers.) If there are no service records or other markings, one has to assume that the fluids/filters/belts/hoses/etc are the original ones installed when the car was new... Link to comment Share on other sites More sharing options...
Guest Double M Posted August 4, 2011 Share Posted August 4, 2011 My mechanic just called. He said that he found these parts at parts.com...ABS Controller... $546Master Cyllinder... $112Which includes the main valve thingy.His recomendation to "fix it" is for me to buy these parts and he'll install them. That will in effect replace the whole system in that area, and hopefully putting me in the position of just maintaining it, like many of you.I have asked for an estimate on the labor... But the prices on the parts alone are too much for me right now. Link to comment Share on other sites More sharing options...
padgett Posted August 4, 2011 Share Posted August 4, 2011 (edited) I am still suspecting a dirty/sticking main valve shuttle, not necessarily and electrical failure.Has the system been flushed ? Completely til the fluid runs clean ?I have annotated Jim's picture a bit. The Main Valve is not part of the ABS body. I suspect the slot has something to do with removing it but never took one apart.Looking in the p&a (group 4) it seems to treat the main valve as part of the master cylinder. Edited August 4, 2011 by padgett (see edit history) Link to comment Share on other sites More sharing options...
Guest Double M Posted August 4, 2011 Share Posted August 4, 2011 Yes, the system was just completely flushed 2 days ago. He said the fluid was contaminated and ugly looking.I found what seemed to be the Master on the same website for $1400 bucks. Last word was he was trying to see if we can just get the valve from this source. I might be leading up to a repair I cant afford to do, which would lead me to sell the car, but I REALLY dont want to do that. Link to comment Share on other sites More sharing options...
padgett Posted August 4, 2011 Share Posted August 4, 2011 So it has not repeated since flushed ? Just went through the manual and parts book. The main valve is part of the boost assembly (master cyl), is not supposed to be disassembled & is serviced as a unit.If it were mine, I would be tempted to just cycle it a number of times (two wire connector). I believe the "thump" in the pedal when you turn the ignition on is the main valve cycling.OTOH lots of things had that restriction in 1988 when parts were available. Guess it just comes down to a matter of trust. Link to comment Share on other sites More sharing options...
Ronnie Posted August 4, 2011 Share Posted August 4, 2011 Speaking as someone who doesn't need to have ABS to feel safe in a car, and if I didn't want to spend a bunch of money (which I don't), I would simply unplug the connector from the ECBM unit in the trunk to prevent the ABS system from activating when braking hard. The main valve, and all other valves, would not give problems again caused by the ABS electrical system malfunctioning. All the power brake (boost) part of the system should still function normally and the car should stop like any other car with power brakes and no ABS.I know that would not be the best way to fix the problem but it would be a cheap way out that would allow driving the car safely without fear of the ABS kicking in and the pedal going to the floor. You would probably have to deal with the yellow ABS light glowing all the time but a piece of black tape should take care of that. Just my 2 cents. Others will probably disagree.DISCLAIMER: I'm not recommending anyone do what I said above. I'm only expressing what I would do under the circumstances stated in this thread. Link to comment Share on other sites More sharing options...
Guest Richard D Posted August 5, 2011 Share Posted August 5, 2011 I have thought about ABS since my first car that had it, two cars actually, a 1991 Mazda Miatia and a company leased Acura NSX and other than showing off to friends when they were new, making 90 degree turns on wet asphalt with my foot on the brake as hard as I could there have been maybe less than 4 occasions where I had to use the ABS in a true emergency, animal running in front car, car with driver on cellphone making a left turn in front of me. I wonder how many of those would have wound up as bent sheet metal or I could have steered out of it. My guess is about 50% I will keep the ABS as long as parts can be found. Link to comment Share on other sites More sharing options...
padgett Posted August 5, 2011 Share Posted August 5, 2011 Back in the day, they used to say a really good driver could beat an ABS. True, if the incident were expected. But for a pure, knee-jerk reaction to something sudden, I really like ABS.I was amazed when GM made ABS standard almost across the board in 1992 but not when quietly shelved it in favor of more air bags a few year later.Remember landing at Stapleton airport and going to the giant AVIS lot a few years ago in a snowstorm and insisting on the ABS they advertised. Only car they could find (and we looked at a lot) with it was a Hyundai. Link to comment Share on other sites More sharing options...
Jim Posted August 5, 2011 Share Posted August 5, 2011 I learned something thanks to Padgett.I was looking at the schematic in the Teves manual and it looked like the main valve was part of the valve block but in looking closer I see the lines did not include the main valve and the main valve is indeed at the end of the master cylinder.I also remembered there were only 6 valves in the block and with the main valve that would have been seven. I have a couple of broken valve bodies in the shelf and sure enough there are only 6 valves in the block.I do have on my shelf two master cylinders by themselves and so I do have two main valves available. This is also known as a main valve solenoid.I didn't look closely to see how it is attached to the end of the master cylinder but am guessing it should not be hard to remove. Link to comment Share on other sites More sharing options...
Guest Double M Posted August 5, 2011 Share Posted August 5, 2011 Thank you so much, especially Ronnie. We've had some disagreements in the past and I'd like to keep them in the past and pave the future with a very sincere thank you. I come to this place, cause I am a car nut, a veteran of owning over 25 cars, mostly vintage and I find myself after all these years behind the wheel of the most complicated of used cars I have ever owned... The Buick Reatta and more importantly to make freinds.:cool:A solution like you suggest may be just the ticket for a temporary solution while I plot a more permanent one between me, my mechanic and my wallet, My ABS light is always on, along with some others and the black tape option has suited me fine.The car has only done the "event" twice and has not been able to be repeated on purpose by me or my mechanic at all, so its hard to fix something that doesnt seem to need fixing. It seems fine now after the total brake flush, but it also seemed fine before hand, except for the two brake failure events I had so far.:confused:As for the debate about weather "to ABS or not to ABS"... let me talk about it...Alot of us here are old school and didnt grow up with ABS, so it gets easily discounted as an option or a gadget we dont need. And yes, a really good driver can make up for the lack of it in most circumstances. Most circumstances. But it isnt most circumstances when that accident happens usually. I have had a few terrible accidents that I am lucky to have survived in cars that didnt have ABS, from a time that the accronym ABS didnt even exist. I was young and foolish then and now I am old and foolish, but the cars I have had in recent years had ABS. On only one occasion can I attribute the ABS from saving me from having an accident, but that doesnt lessen the fact that it may have in other situations too. Too be honest the time that it did save me an my passenger could have been avoided if I was paying more attention to the road and not my lovely female passenger... Other times they came on and weather or not they helped is debatable, but they did their job easier than me pulling a "Starsky & Hutch" type of skidding manuever. I recognize the benefits of ABS and strongly encourage people to get a car with them, but for me in particular, I dont mind not having them. They have NEVER worked on my Reatta, and the car I drove for 4 years prior, didnt even have them, so I aint going to miss them. But I do miss that Female passenger... I digress...Like Ronnie (thank you again) said, I dont encourage anyone to disconnect their ABS, but for this particular situation it may be the way to go for me, so I can get back on the road and drive to the job that makes me the money to afford the proper fix. I dig the Reatta and all its features and proud to own one and would like to keep it original if possible. If I didnt apprciate odd, rare vehicles with hard to get parts, I would be riding Italian Scooters, that is for sure!:eek: Link to comment Share on other sites More sharing options...
Jim Posted August 6, 2011 Share Posted August 6, 2011 I guess I am ready for the old folks home. I went and looked at the two master cylinders I have on the shelf and see one of the main valves is gone. The only person that could have removed that valve is me but I absolutely do not remember doing it.The other valve is still in the other master cylinder and it is just held in with a snap ring. I didn't take it out but it looks like all you would need is two small screw drivers to get the snap ring out and then just pull the valve out of the master cylinder. Link to comment Share on other sites More sharing options...
padgett Posted August 6, 2011 Share Posted August 6, 2011 Jim: On the one that is removed, do you see a straight round passage with about four ports in it ? That is what I would expect.My hypothesis is that you have some grit in that passage that is occasionally jamming the return of the shuttle.I *suspect* that under the snap ring and the valve, there is a O'ring seal and there may be seals on the shuttle you should be prepared to replace but without seeing the assembly removed just do not know. However the solenoid is not that strong so suspect it is just a precision fit to the M/C (and could be matched which might explain why it is not servicable according to GM).At least this failure is leaving you with some braking. Link to comment Share on other sites More sharing options...
Rawja Posted August 8, 2011 Share Posted August 8, 2011 There's a procedure for checking the resistance of the individual valve solenoids in the valve block.If it would be a help I can loan your mechanic the breakout box the dealers used back in the day. I also have a complete master sitting in a box if you're interested.It's also possible the aforementioned crud in your fluid jammed up the works and caused your problem. I'd drive it and see if the problem returns again. Link to comment Share on other sites More sharing options...
Guest Double M Posted August 8, 2011 Share Posted August 8, 2011 Well, I have the car back. First. The car stops smoother than ever since the brake flush, a big difference.Second. I drove it all weekend and to work today w/o incident.Third. I took it home in hopes of disconecting that computer in the trunk, while I try to locate and or /sort out what I actually need, a main valve, whole assembly - but it looks hard wired in. How would one disconnect that Braking Computer in the trunk? Link to comment Share on other sites More sharing options...
Guest Mc_Reatta Posted August 8, 2011 Share Posted August 8, 2011 One end has a metal tab that is held in a slot. The other end has a wire clip that is held in place by tabs on the EBCM. Pull out and up on the wire clip until it is free and then the connector will pivot up on that side. Continue to pivot up while pulling the entire connector away from the EBCM and the connector will come free.Installation is the reverse, seat the tab into the slot on one end and then pivot the connector down and in until the wire clip can be snapped into its retainer on the other end.Be careful not to use undo force and damage any of the pins. Link to comment Share on other sites More sharing options...
padgett Posted August 8, 2011 Share Posted August 8, 2011 I push in on the clip util it releases the long connector. Tab is on cable end. Link to comment Share on other sites More sharing options...
DAVES89 Posted August 10, 2011 Share Posted August 10, 2011 (edited) I checked the resistance at the main valve pins. I get 4.9 ohms on my Red and 4.7 on the Teves master cylinder I have in inventory. Could someone check and get back if that is a good reading to get the ABS code to stay out? I also have a code "21". BTW just for grins, We did swap out the main valve and that did no good. There was some gunk [but as stated before the light does come back on] in the valve body. I am very comfortable with the testing that my buddy did, the wiring is good. Even for grins we swapped out the low pressure switch, no differ Edited August 10, 2011 by DAVES89 (see edit history) Link to comment Share on other sites More sharing options...
padgett Posted August 10, 2011 Share Posted August 10, 2011 Is 21 the only code you have ? Will measure some of mine when I get a chance. Link to comment Share on other sites More sharing options...
Guest Mc_Reatta Posted August 10, 2011 Share Posted August 10, 2011 Readings are in the acceptable range for the valve. (2 to 5 ohms)If you are satisfied that there isn't an issue (continuous or intermittent) with the circuits between the EBCM and the valve, the valve and ground, and the EBCM and the valve body, then the EBCM is source of the problem.The code would be set during the key on tests the EBCM performs before you even drive the car. It is responsible for the thump in the pedal at start up. Do you feel the thump? You mentioned you had swapped out the EBCM with another one in your back stock, but did you swap with a known good unit? (From your Red maybe?)If code is set, it will latch for the entire key on cycle and keeps the yellow light on. Link to comment Share on other sites More sharing options...
Barney Eaton Posted August 10, 2011 Share Posted August 10, 2011 (edited) I had never looked into the "Main Valve" function before. So I did some reading...Under normal conditions, it is in a unactivated position and the open port appears to be nothing more than a fluid return line.When ABS is activated, the solenoid is picked and the main valve spool shifts and has high pressure going thru the secondary port and the ABS solenoids then control each wheel.I pulled a main valve and there is no way of cleaning anything but the outside.You can take a resistance measurement, but I put 12V across the pins and listened for the "click". A stuck spool will not "click" but you will get a good resistance measurement. Without a detailed schematic, there is no way of telling what sets the 21 code.It could be as simple as the ABS computer sensing the coil resistance, but that would notshow a stuck valve. Since there are only 2 pins on the connector, there is not a electrical way of sensing the valve position.Attached is a photo of the unit out of the master cylinger. Edited August 10, 2011 by Barney Eaton (see edit history) Link to comment Share on other sites More sharing options...
Guest Mc_Reatta Posted August 10, 2011 Share Posted August 10, 2011 Agree with your analysis Barney.The EBCM does not actually know if the valve opens or not. It only senses the voltage or current draw at its control output and if not within an acceptable range, it turns on code 21.Feeling for the thump in the pedal at start up is the only indication that the valve actually opens as it should.If the EBCM does sense for current draw rather than voltage it might see an out of spec draw from the solenoid trying to overcome extra resistance say due to dirt or debris in the chamber keeping the solenoid from moving as freely as it should. Without more information we can't know for sure. Does appear that it is an interchangeable part though. So if you don't feel a thump while doing the brake test, or it fails the resistance check, you should be able to replace with another valve without the hassle of replacing the entire Teves hydraulic unit. Replacement of the o-rings with new may be a wise move if interchanging along with carefully wiping out the chamber. Hopefully the rings are not a hard to find size. Link to comment Share on other sites More sharing options...
padgett Posted August 10, 2011 Share Posted August 10, 2011 Good news just to me if you get the "thump" and there is no error until you are moving than it points to a wheel sensor line - after POST I do not think the main valve is exercised unless ABS is needed.POST - power on self test. Link to comment Share on other sites More sharing options...
DAVES89 Posted August 10, 2011 Share Posted August 10, 2011 Guys can you move your comments over to the thread I started? I don't want to confuse what Double M has started. Link to comment Share on other sites More sharing options...
Guest Double M Posted August 10, 2011 Share Posted August 10, 2011 Never ever got a thump. In fact before this incident and leaving ot with my mechanic for 3 weeks and got a Brake Fluid Flush, ny ABS light would go out at start up and come back on after reaching a few MPH.Now... It stays on all the time. Still have not disconnected the computer in the trunk. Link to comment Share on other sites More sharing options...
Guest Mc_Reatta Posted August 10, 2011 Share Posted August 10, 2011 DoubleM, did you or your mechanic check the resistance of the main valve?If you still don't get a thump after your flush, or the resistance of the valve isn't between 2 and 5 ohms you might want to try changing out this valve.The purpose of this valve is to prevent too much pedal travel when in ABS mode. If it doesn't open, your pedal could easily go most of the way to the floor which I think was your original complaint. Link to comment Share on other sites More sharing options...
Guest Double M Posted August 11, 2011 Share Posted August 11, 2011 DoubleM, did you or your mechanic check the resistance of the main valve?If you still don't get a thump after your flush, or the resistance of the valve isn't between 2 and 5 ohms you might want to try changing out this valve.The purpose of this valve is to prevent too much pedal travel when in ABS mode. If it doesn't open, your pedal could easily go most of the way to the floor which I think was your original complaint.If we could get a replacement Valve, that would solve the problem for sure. We have not been able to locate a source for JUST the valve. It comes with the whole ABS assembly, maybe with the master, but there seems to be no part number for just the valve.So w/o that option, I am trying to persue disconnecting the ABS computer in the trunk, but have had no luck removing the conector. Here is a pic...I push up on the tab, but pulling on the wire, it seems to want to split in half... Link to comment Share on other sites More sharing options...
Guest Mc_Reatta Posted August 11, 2011 Share Posted August 11, 2011 You just need to persevere. Push the tab in your photo away from the wire bundle and then pull out on the wire bundle and this end of the connector will start to pull away from the EBCM. After it has pivoted a way towards the front of the car, the entire connector will come free from the box. Installation is the reverse, seat the rear of the connector into the slot at the rear and piviot the wire end of the connector down and into the ECBM until that tab latches.If you intend to leave the connector unplugged for awhile, I would recommend sealing both the connector and open end of the EBCM to keep dirt and moisture out. Maybe a plastic sandwich bag over the connector and some tape over the socket on the EBCM? It looks like the main valve was not intended to be replaced in the field so it probably never had a published part number. But that doesn't mean that it has to be so.Jim took one out of one of his units, so I'm sure he can come up with one he could supply you to try. Since he pulls the pump/switch/accumulator off Teves he finds in yards, he could remove main valves as well and supply them if there is demand and it proves to be a safe practice. Would just clean up the valve and test for resistance and action and replace the o-rings with new.Would give us another option for keeping our Teves in repair and not need to replace the entire hydraulic unit if all that is needed is this valve. Link to comment Share on other sites More sharing options...
DAVES89 Posted August 11, 2011 Share Posted August 11, 2011 Double M I have just bought 2 Teves master cylinders for $30.00 each [pulled by the yard]. They didn't have the pump and motor but I didn't care, I just was after the main valve. Anyhow the first one I got had resistance of 4.9 [i bought the first Teves unit w/o testing thinking that the valve resistance would be good, silly boy], but I checked the second and that read 4.2 ohms. There is one more out there that reads aprox. 4.5 ohms, that I could get for you. PM me if you want it for my cost of $30.00 plus whatever freight would be for an entire Teves unit [$15.00?]. It would include the pump and motor. Link to comment Share on other sites More sharing options...
padgett Posted August 11, 2011 Share Posted August 11, 2011 If he passes, I'll take it. Link to comment Share on other sites More sharing options...
DAVES89 Posted August 11, 2011 Share Posted August 11, 2011 Padgett, You drive such a "hard bargain" that I suppose I will have to throw in at least one "rebuildable" front sensor for you, huh? lol Link to comment Share on other sites More sharing options...
padgett Posted August 11, 2011 Share Posted August 11, 2011 I just recognise a good buy when I see one. Link to comment Share on other sites More sharing options...
DAVES89 Posted August 11, 2011 Share Posted August 11, 2011 You guys should check out Car-Part.com--Used Auto Parts Market and look at brake boosters. There are 13 brake boosters in Florida at $50.00 or less, and 5 in New York at $50.00 or less. I would just ask them to use a multi meter and check the resistance of the main valve. If under 4.5 ohms buy it... Link to comment Share on other sites More sharing options...
Ronnie Posted August 11, 2011 Share Posted August 11, 2011 I fail to see why everyone is jumping on the grab a main valve bandwagon. As far as I can tell from reading both threads about a code 21, changing a main valve has not cured the code 21 problem at this point. Did I missing something? Link to comment Share on other sites More sharing options...
DAVES89 Posted August 12, 2011 Share Posted August 12, 2011 I fail to see why everyone is jumping on the grab a main valve bandwagon. As far as I can tell from reading both threads about a code 21, changing a main valve has not cured the code 21 problem at this point. Did I missing something?On my Red's unit and the first one I got from the u pick the resistance of the main valve was 4.9 and 5.1 ohms. The one I picked up today had a resistance of 4.2 ohms [within the tolerance of the spec on code 21]. I checked the resistance of my Black Reatta and the resistance was 4.2 as was the Jim Finn checked on his car. This could be important as the main valve is really just a selonoid switch. I will know more next week as that is when I go back to my buddy's house to hopefully end this episode... Link to comment Share on other sites More sharing options...
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