BrentS Posted June 10, 2008 Share Posted June 10, 2008 My '89 Reatta w/ 120K mi has lost the power brakes on very hot days (90+ degrees) 4 times now; and the red brake light comes on and the CRT shows "Low Brake Pressure...". The brakes don't work until you shut the car off for a few hours (maybe to cool?). I've tried to have dealer fix it, but the problem didn't happen for them. They replaced the pressure switch anyway, which seemed to have been a waste of money. I replaced the relay on the fire wall because it was cheap & easy, and the accumulator was replaced last year (it failed). All 4 brake pads are good, and the dealer flushed & bled brakes system 6 months ago.Any ideas? Anyone experience losing the brakes when it's hot (it's not fun). Link to comment Share on other sites More sharing options...
harry yarnell Posted June 10, 2008 Share Posted June 10, 2008 Sounds like the pump. Are you sure you replaced the RIGHT relay? Link to comment Share on other sites More sharing options...
BrentS Posted June 10, 2008 Author Share Posted June 10, 2008 I'm fairly sure I replace the right relay; I replaced part no. 25553347. I'll double check which one I replaced on the firewall (i.e. middle, left, etc.).I am currently reading sect. 5E1 in the service manual and fortunately it appears relatively simple, in that if the pump stops coming on to pressurize the accumulator, it seems to only be: relay, pressure switch, pump/motor assy. Does that seem right? Unfortunately, I bet the pump/motor assy is expensive, right? Anyone have a part number for it, so I can brace myself? Link to comment Share on other sites More sharing options...
BrentS Posted June 10, 2008 Author Share Posted June 10, 2008 Ok, I just checked; I replaced the relay mounted in the middle (between 2 others) on the firewall. Link to comment Share on other sites More sharing options...
DAVES89 Posted June 10, 2008 Share Posted June 10, 2008 I believe Jim Finn has a used good working pump. He has always been reasonable. I don't have his e-mail address. [i cleared out a bunch of stored e-mail addresses and by mistake his was one] Link to comment Share on other sites More sharing options...
BrentS Posted June 10, 2008 Author Share Posted June 10, 2008 Ok, thanks. Yep, I've used Jim's parts before. I check w/ him. Link to comment Share on other sites More sharing options...
Guest EDBSO Posted June 10, 2008 Share Posted June 10, 2008 For me it sounds like a brake flush is required.I know you have been told it was recently done but it sounds as though the fluid under the high temperatures under the hood when it is over 90 degrees is boiling and can not be brought up to pressure.I had a similar problem and a flush fixed it. Link to comment Share on other sites More sharing options...
BrentS Posted June 10, 2008 Author Share Posted June 10, 2008 Thanks for the response EDBSO, but I just don't think that's it. Mainly, because it seems pretty clear that the pump/motor assembly simply just stops pumping. Plus; I thought brake fluid only boils at temps well above 200F, no? Like when a mechanic forgot to re-install some return springs on another of my car's calipers, and the pads stayed on the rotors continuously. That was also not fun.I can imaging the fluid boiling at lower temps on the intake (low pressure) side of the pump circuit, but imagine you would still hear the pump running and trying to pump, no? This doesn't seem to do that.Does anyone know what the main brake relay do? It's the one on the right, and seems to be the same part number. I could change that for only a few dollars.Thanks. Link to comment Share on other sites More sharing options...
Guest EDBSO Posted June 10, 2008 Share Posted June 10, 2008 In my case the pump would run continuously. Link to comment Share on other sites More sharing options...
Guest Greg Ross Posted June 10, 2008 Share Posted June 10, 2008 I believe all three relays on the firewall are or were the same PN. When I first bought my car way back when, I thought the three relays sat in a pretty hot spot right there above the exhaust so just replaced them all. Link to comment Share on other sites More sharing options...
BrentS Posted June 10, 2008 Author Share Posted June 10, 2008 Ok EDBSO, that would make more sense. My problem is that the pump stops running, and won't run until car is off for many hours.Ok, did more reading on 5E1, and found a really helpful troubleshooting section for "Pump does not Run". Unfortunately, it looks like I need to have the problem happen again, in order to start the troubleshoot process. And, my luck, it will happen when or where I can't troubleshoot. Oh well. I'll keep at it.Now, I'll move over to troubleshooting the E041 Engine Controls error that's been recently coming up, too. Ughh. Link to comment Share on other sites More sharing options...
Ronnie Posted June 10, 2008 Share Posted June 10, 2008 <div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> Unfortunately, it looks like I need to have the problem happen again, in order to start the troubleshoot process. And, my luck, it will happen when or where I can't troubleshoot. </div></div>You can't fix it if it's not broken.Carry a volt meter, paper towels and the Service manual with you. If the pump stops running going down the road that is the best time to troubleshooting the problem anyway. Link to comment Share on other sites More sharing options...
Guest Drake Posted June 10, 2008 Share Posted June 10, 2008 Can't help with your brake problem, but recently had the same error code for my 89. My MAF sensor retired. New MAF sensor, reset codes, and all is fine (FOR NOW). Link to comment Share on other sites More sharing options...
Barney Eaton Posted June 10, 2008 Share Posted June 10, 2008 The correct relay for our Reattas is still available, the part number varies with the manufacturer. See photo below.All the relay shown will work but only one has the correct latch for the connector and the correct slot on the back to fit into the bracket. Link to comment Share on other sites More sharing options...
jonlabree Posted June 10, 2008 Share Posted June 10, 2008 Duh, wich one????????? Link to comment Share on other sites More sharing options...
Guest crazytrain2 Posted June 10, 2008 Share Posted June 10, 2008 Read a similar story, person put some foiled insulation between pump motor and engine to minimize engine heat exposure. And ran some tubing from front of the car to the pump motor area to increase air flow and cool the pump. This apparently worked and more importantly helped identify the real cause.For what it's worth I thought I'd mention. Link to comment Share on other sites More sharing options...
Guest Drake Posted June 10, 2008 Share Posted June 10, 2008 Barney, I'll go for the GM relay in the middle! ???? Link to comment Share on other sites More sharing options...
BrentS Posted June 10, 2008 Author Share Posted June 10, 2008 Well, it's still 85 degrees out here on Long Island, so we'll see if it happens on the way home today. I kinda wish it does, just so I can troubleshoot it more. If it doesn't, I'll take Ronnie's advice and keep a troubleshoot kit (w/ the pages from the manual) in the car; all ready-to-go.The insulation/tubing idea is sort of interesting.As far as the E041 code: the mass airflow sensor was replaced last year, and the service manual only speaks about the Cam Sensor circuit for that code, so Drake your MAF sensor experience is a little puzzling. Link to comment Share on other sites More sharing options...
Guest Drake Posted June 11, 2008 Share Posted June 11, 2008 Sorry Brent, read my notes too fast. My error code was E034 not E041. Thanks for the correction. Link to comment Share on other sites More sharing options...
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