Moparchat - Home of MOPAR enthusiasts worldwide!



Go Back   Moparchat - Home of MOPAR enthusiasts worldwide! > Technical Forums > Performance Talk

Click here to search for Mopar cars and parts for sale.


Reply
 
Thread Tools Display Modes
  #1  
Old 03-19-2001, 04:51 PM
383 383 is offline
Inactive User
 
Join Date: Dec 1999
Location: Rock Hill, SC
Age: 53
Posts: 76
Angry

I've been fighting a brake problem for some time now, and yesterday I think I fiqured out the problem is. I've got a 70 RR with drum brakes all the way around. 10" frt, 11" in the rear. When I take the car out after awhile Ill have pressure build up in the lines and cause the frt drums to engage. The pedal will get rock hard, and I will have to crack the both lines at the master to get the pressure off. I've replaced the master twice, the proporting valve, and all the brake hardware on all 4 wheels, and still it will build up pressure. I notice yesterday that the brake pushrod will not let the master cylinder valve return to it's rest position. I tried adjusting the brake light switch but I still couldn't get enough room for it come all the way back. I think my pushrod is to long. I got the car in 98, with no fender tag, or broadcast sheet, so Im guessing it's suppose to be manual brakes. Does anyone know what the proper length for the pushrod is, also has anyone used the adjustable pushrod from Mancni Racing I was wondering if that would cure my problem.
Reply With Quote
  #2  
Old 03-20-2001, 01:28 AM
mshelly mshelly is offline
Inactive User
 
Join Date: Oct 2000
Location: Mountain View, CA USA
Posts: 92
Default

Had the same symptoms on my '70. I could drive normally for about 1/2 hour and then the brakes would to apply themselves slowly until all I could do was spin the rear wheels. Let it sit for an hour and it was O.K. again.

Turned out to be a defective check valve in the "new" master cylinder.

Every time I go to the discount auto stores I get burned!
Reply With Quote
  #3  
Old 03-20-2001, 01:37 AM
mopartec mopartec is offline
Senior Member
 
Join Date: Dec 1999
Location: atascadero ca u.s.a.
Age: 62
Posts: 698
Default brakes

thinking back to my 70 bird mine was 11 at all 4`s.mine was manual. i have never found a spec in any manuals. see if you have a build sheet under your back seat that may help. if you pull the master from the booster will the master come back to rest. then it might be a bad or wrong power booster. the new booster is always supplied with a new rod. i hope this helps
Reply With Quote
  #4  
Old 03-20-2001, 02:12 AM
PRO PRO is offline
Inactive User
 
Join Date: Nov 1999
Location: Grand Junction,CO.USA
Posts: 1,573
Default

For starters your RR should have 11" brakes front and rear minimum,it could also have come with disc up front and 10" on the back if it had a dana or 11" if its an 8.75,seems like someone stole your 11" front drum setup or more likely they stole your disc brakes,anyhow your problem is VERY common,if indeed you had disc brakes originally the pushrod is a different length,this is true for Power disc brakes too,if youll go to a boneyard and retrieve a B body pushrod from a car with 10" front brakes everything will work ok,Ive also seen this prob when someone uses a drum brake master cylinder on a disc brake set up,the reason it hangs up after a short drive is in the outlet port of the master cylinder there is a residual check valve whichs maintains a constant 2-10 psi without any brake pedal being applied,this keeps the wheel cylinders from retracting so far,otherwise the pedal will go almost to the floor on the first stroke,but on a disc setup it applies the brakes enough to drag the car to a stop....PRO...
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
brake drum ?? gerard Restoring your MoPar (Tricks & techniques) 3 06-19-2009 11:40 PM
64 drum brake problem sjzdx Restoring your MoPar (Tricks & techniques) 10 11-30-2007 12:44 AM
WTB 9 in. drum brake hub ass. 67Dart360 Rear Wheel Drive - Parts for Sale 0 05-21-2004 11:48 PM
Power drum brake problem Hustlestuff Performance Talk 6 04-29-2004 04:59 PM
Brake Drum ? 76Duster Performance Talk 10 05-22-2003 01:00 AM




All times are GMT -4. The time now is 01:25 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
. . . . .