Need help troubleshooting brakes

[1929Chrysler]

Three years ago I had the entire brake system rebuilt on my '29 Chrysler. This included the master cylinder and wheel cylinders all re-sleeved and new cups installed. Also have new brake lines and pads all the way around. The car has less than 500 miles since the rebuild and when it was new the pedal felt perfect. Late last year I noticed the pedal had to travel a lot farther for the car to stop. This week I notice the pedal goes all the way to the floor and I feel no resitance. I obviously can't drive like this.

I checked all the flare connections and I don't see any obvious leaks. Please help me with this as I am not entirely familiar with this braking system. It does have a brake can resevoir that is mounted to the fire wall and it appears that brake fluid would gravity feed down to the master cylinder when needed?? Is this how the system works? Yes, there is brake fluid in the resevoir.

Thank you very much for your help.

Dan

[Guest oldodgeboys]

Dan- I'm not familiar with the 29 system, but your symptoms may indicate an internal leak in the master cylinder...the piston seal may be damaged of deteriorating. Just some thoughts. Good luck, Gus

[keiser31]

That usually happens when a car sits. I would re-bleed the brake system from the start and see what happens before disassembling.

[Guest 1930]

The reservoir does feed the master below but also allows for return and that is why they should not be overfilled. You should try and remember how much fluid was originally put in can, if there is substantially less than you prob. have a leak somewhere. Pull the drums off and you might find your leak, might also be that the system was not originally bled of air completely, maybe there was air in any one one of the lines that has worked its way down. Either way you have only a couple of options and that is a leak in system or air in the system. I would myself bleed all 4 wheels with the drums off that way you kill two birds with one stone. I just also remembered one other thing and make sure you have correct cap in your can. The original correct cap was made up of three seperate pieces and without all three your fluid will not only not vent correctly but you will also be more subceptible to air and or fuid entering/escaping your can. Most cans are missing correct parts in cap. I can show you these pieces if you need them.

[1929Chrysler]

Quick update: I had no pressure going to the wheel cylinders so I removed the main brake line coming out of the master cylinder and installed a bolt in it's place to perform a test. When I pressed on the pedal with the bolt in place there was no resistence so the problem appears to be the seals in the MC. Any ideas where I can find new seals?? Remember, it has already been re-sleeved.

Yes, I am using DOT 5 silicone brake fluid.

Dan

[Guest oldodgeboys]

<span style="font-family: 'Arial Black'">Brake fluid compatability is unlikely. As you take it apart, you will probably find a nick in the seal. Debris may have come into the system during the last rebuild. It happens.

Good luck

Gus</span>

[nearchoclatetown]

Not saying you did it, but brake fluid can not be mixed. Once you use silicon you can't use regular with it. Most resleeved cylinders are taken back to original size. If you take the cylindr apart you should be able to measure it. I do not know anyone that has used silicon fluid with success, just an internet opinion.

[JFranklin]

I have successfully used silicone brake fluid in 4 cars to date with no problems. A 1936 Chevrolet, 1948 Plymouth, 1952 Dodge truck, and 1966 Ford Mustang. The problem most likly is the piston or other part in the master cyl.

[Guest simplyconnected]

DOT-5 is not compatable with some seals. The brake switch on my '55 M/C is always non-functional due to DOT-5. Guys just abandon the hydraulic switch and install a mechanical at the pedal assembly. Cars with ABS stay far away from 5. I'm not trying to bash 5, but there are many very good reasons NONE of the oem's us it.

I suggest you remove the DOT-5, flush the lines real well, and fill with DOT-3. After a few months, change the DOT-3 again, just to make sure nothing was compromised. All seals for your M/C are compatable with good ol' DOT-3. Five bucks will buy a whole quart.

[Guest oldodgeboys]

<span style="font-family: 'Arial Black'">I agree, brake fluid compatibility should be considered.

In this case however, there appears to be only an internal leak to the master cylinder...could it be that only this seal is incompatible with the fluid? What about leaks at the wheels and external at the master also?

Unless a different material seal was used for the master piston only...? Otherwise, I still think a mechanical failure at the master piston seal may be at fault.</span>

[1929Chrysler]

I did much research on the silicone before I decided to go with it. One of the reasons I did is because it does not harm paint and that is important when a chasis and fire wall and brake can resevoir are painted pretty. The other reason is that it does not absorb moisture like the dot 3 and given the fact that my car is driven maybe 200 miles a year, I did not want corrosion to start taking it's affect with the dot 3 on my system.

Now, for every 3 guys I have heard who have had problems with silicone and curse it, there are 10 guys who swear buy it. These guys have had it in there system for years with thousands of miles with no problems. That's not to say that silicone is gauranteed to be trouble free. The interesting thing with my brake system is that the wheel cylinder seals are bone dry after three years. I bought the seal kit in my master cylinder on e- bay about 5 years ago and may or may not be made from the same rubber type as the wheel cylinders. I have heard two different theories on getting silicone to work properly. The first one is to get seals that are compatible with silicone. Well, my question is HOW DO YOU KNOW WHAT IS COMPATIBLE AND WERE DO YOU GET THEM?! The second theory on getting silicone to work properly is to provide the system with a good quality DOT 5. This second theory comes from Apple Hydraulics who resleeved my MC. He says that the majority of his customers who have had problems with Silicone comes from buying the cheaper stuff. He didn't give any recommendations for a brand name to use. Does any one have any recommendations out there??

I will report back to you on what I find once I disassemble the MC. At this point I am not giving up on the silicone just yet. Thanks again for all your help and input.

Dan

[Guest outlaw car man]

I just went thru a LONG process with my brakes on a DL6. One of the main culprits was a bad bleeder valve.

Car had been sitting for MANY years and the fluid was crystallized in the wheel cylinders. Just make sure they are OK too. Probably to late but I'd agree with John on bleeding the system first-

Good luck with it-

OCM

[Guest simplyconnected]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 1929Chrysler</div><div class="ubbcode-body"> ...the majority of his customers who have had problems with Silicone comes from buying the cheaper stuff... Does any one have any recommendations out there??</div></div> Dan, I have a good answer for you. My Harley-Davidson motorcycle came with DOT-5.

Call Harley! Most dealerships are close to everybody across the country, and they ALL have DOT-5.

Whatever brake fluid you use is totally up to you. If you have done your homework, know what the oem's are using today, and realize what came in your car, you make your choice and deal with the consequences associated with it. Trouble comes when Purists insist on using original equipment, then change to incompatible fluid.

My understanding is, ALL of today's seals are compatible with ALL DOT's of brake fluid. If you are still unsure, get with Raybestos, Bendix, Federal Mogul, etc.

Hope this helps. - Dave

[1929Chrysler]

Dave, You make an excellent point on the Harley Davison systems. It's my understanding they are all Dot 5 and they have it down pat with no problems. I have a buddy who has a '29 model 65 Chrysler just like mine and he too has been using silicone for years with no problems. I just wish someone could point to a common denominator with what the specific issue is with DOT 5 if there is one. In any case I don't even know if it is a silicone problem until I tear the master down.

I'll let you know soon.

Dan

[Guest simplyconnected]

H-D has successfully used DOT-5 since at least 1990. Mind you, their brake systems were designed for DOT-5. THAT is the common denominator. Your system has seals and pressure switches that were designed specifically for DOT-3.

Idiot owners (like my cousin) put DOT-3 in to top off his H-D M/C. We had to change all the lines, disassemble, and clean everything in alcohol. Then, back to DOT-5.

The same thing happens with car owners, thinking the more costly DOT-5 MUST be better fluid, they add that to OEM DOT-3 systems. (Same results.)

I don't want to get off subject, but I got my wife's Dodge Intrepid CHEAP because someone mixed antifreeze (green + orange). It turned to mud and overheated the engine. For the cost of a major overhaul, she got a nice car.

Bottom line: Stick with what it was designed for. You won't have issues. Every cloud has a silver lining: Changing DOT-3 every three years keeps my bleeder valves working AND fresh DOT-3 sucks-up and disburses any moisture. That makes it a rust inhibitor. I believe DOT-5 has no rust inhibitor, so water pools in the lowest places, and rusts. That's why ABS systems stay away. They can't do ICE in winter.

Dave

[1929Chrysler]

Just disassembled the MC. One of the seals has a tear in it. As soon as I can figure out how to post pictures I will show everyone.

Dave, I'm certainly not going to argue with you between DOT 3 and 5. I am by no means an expert in the auto field and I can gaurantee you probably know 100 times more than I do about cars than I do. I am the type of guy who has to be shown hard scientific facts as to why something doesn't work. So far I have only heard theories. And believe me... I'm not saying you are wrong in your analysis. I am just questioning specifically what is the exact reason, if there is one (ie: tolerances, rubber swell, viscosity...)as to why DOT 5 won't work in a vintage car. Why does it work for some guys with absolutly no problems while others stuggle? Doesn't Harley's systems have seals in them too? If their sytems were designed for DOT 5, what is so different?

You are probably right when you say 5 can't disburse moisture like 3 can but if I change the 5 every couple of years I will surely get rid of any moisture that may be in the system. I really like the fact that the 5 will not ruin my paint and for that reason I am really hoping I can get this to work. If seals start tearing on me repeatedly, then I may start to believe that the DOT 5 has something to do with it.

Just for the record.. My brake system when rebuilt was a virgin system. It has never seen DOT 3 so there is no question of cross contamination.

Dan

[Guest simplyconnected]

Dan, it's the TYPE of seal material used that is either compatible with your fluid (or not).

Ever wonder why there are so many transmission fluid types? Wouldn't you think one good type should be sufficient for all tranny's? Doesn't work that way, GM and Ford used different materials and only their types of fluids are compatible. Older brake seals are that way too.

For eons, European seals were notorious for leaking. Early Mercedes engines had a full PAN underneath them to catch drips. The problem was a lack of polymer choices but they did the best they could with what they had. Now we have lots of choices, but they aren't all compatible with all fluids.

You mentioned swelling (certainly a compatibility issue), but your seal tore. Was it stiff or hard? Was it just old? Or did it get old prematurely? (Shrinking is a sign of another compatibility issue.) I am worried about all three of your brake hoses. M/C and hose rubbers should last at least 100K miles or ten years.

My point is, you obviously need compatible materials if you stick with a particular system. Therein lies the key. My Harley DOT-5 brakes NEVER had issues. I depended on them for over fifteen years. I maintained them, but they never failed, front or rear. Two different systems: front is dual-disk and rear is single disk brakes.

I hope this helps.

Dave

[Guest simplyconnected]

I forgot to add:

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 1929Chrysler</div><div class="ubbcode-body"> ...As soon as I can figure out how to post pictures I will show everyone...</div></div> Dan, send your picture to me and I will post it for you. Get a close, clear, and as high of resolution picture as you can. Send it to:

simplyconnected@aol.com

[RobV]

I work for H-D, and was a mechanic for many years. DOT5 will work well in older brake systems, we convert old DOT3 systems all the time. I converted my '29 DA to DOT5 with no problems.

One thing that is very very important when converting old systems is to completely flush the braking system with a solvent to remove the DOT3. I use regular old rubbing alcohol to do the rubber lines, and lacquer thinner for the metal parts. Also, be sure to replace ALL of the old seals and rubbers when you do. If there is any seal that is reused, it will have consequences. DOT3 and DOT5 cannot be mixed, they form a very nasty gel when you do.

BTW, I still use the original brake lines when I convert, they don't seem to have a problem as long as they are flushed and cleaned well.

[1929Chrysler]

I would think that the manufacturers of DOT 5 would have been sued by now from someone for brake failure due to using it in a non compatible system. Attorneys I am sure would have warnings plastered all over the bottle if this was the case.

My bottle's warning says: Do not use on anti-lock braking systems. DOT 5 brake fluid should not be used in brake systems containing Dot 3 or DOT 4 brake fluid. DOT 5 Silicone Brake Fluid may be used in brake systems previously factory filled with DOT 5 Silicone Brake Fluid, "OR" in rebuilt/replaced brake systems.

I would think there would be warnings on the bottle of the DOT 5 not being compatible with certain rubber seals.

I wonder if even after a sytem with DOT 3 is completely flushed out and Dot 5 introduced, small amounts of the 3 still in the system (unknown to the car owner) combine with the 5 and the two fluids chemically react to swell/eat the rubber? The small, tiny amount of 3 would not be enough to form the nasty gel but would be enough to create problems with the seals. Just a theory, but what do I know!

In any case, after looking closer at the seal that is torn, it sits next too a steel washer inside the system. This steel washer has a rough sharp burr that matches the pattern on the rubber washer so I think I have found what caused the failure. Other than that the seals don't look swollen and pretty much still look brand new.

I have no idea how to download pictures from my camera to the computer so when my wife helps me with this, I promise I will show the pictures.

Dan

[Guest simplyconnected]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 1929Chrysler</div><div class="ubbcode-body">I would think that the manufacturers of DOT 5 would have been sued by now from someone for brake failure due to using it in a non compatible system. </div></div> Why would the fluid company be sued? They aren't pouring it into anything, YOU ARE!

Don't you think your neighbor would sue YOU, if you caused his brakes to fail? You can make book on it, especially if someone was badly injured or died.

You never answered, are your failed seals hard or brittle? New seals don't just split.

[nearchoclatetown]

Simpleconnection, is there a GOOD reason you continue to argue? You've done this with just about every topic you respond to. He is satisfied with DOT 5, so let it be!

[Guest oldodgeboys]

<span style="font-family: 'Arial Black'">Dan-

Congrats on finding the problem as was originally suspected. The simplest explanation is usually the case.

"your symptoms may indicate an internal leak in the master cylinder...the piston seal may be damaged..."

oldodgeboys</span>

[Guest simplyconnected]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: nearchoclatetown</div><div class="ubbcode-body">Simpleconnection, is there a GOOD reason you continue to argue? You've done this with just about every topic you respond to. He is satisfied with DOT 5, so let it be!</div></div> Are you a censor? If you notice, I have stuck to Dan's topic at every point, and have NOT disrespected his decision to use fluids of his choice. I use both as I have stated, and offered to help with picture postings. If you have something constructive to add, go for it, Hershey-Boy. Personal attacks is NOT what this forum is about.

Dave

[gundog99]

This may seem a silly question. How do you test for which type of DOT is in the brake system?

[Guest simplyconnected]

That's the best question I've heard about brake fluids, gundog. Both are absolutely clear when new.

DOT-3 is glycol-based. It eats paint but it is also water soluable (like antifreeze). It will attract and readily mix with water like Scotch Whiskey. Old DOT-3 will look brown or redish from rust inside the brake system. It has a strong brake fluid odor. You can hose it off easilly.

Dot-5 (being silicone-based), floats on top of water, and doesn't mix. It can be cleaned with alcohol, like RobV said.

This is a stretch, but I'm going to try some DOT-5 on my windshield in place of Rain-X. It should work if I clean with alcohol first.

[RobV]

The DOT5 I get (which should be no different than any other DOT5) is purple in color. DOT3 is clear or yellowish. However DOT 5.1, which I have never seen in person, is supposed to be 'crystal' clear.

Don't mistake your DOT 5.1 bottle for your water bottle!