Brake situation

Dominique Williams

Dominique Williams

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Had my mechanic adjust the timing and distributor and the temperature got alittle bit hot in the engine bay that it heated up my master cylinder which cause my back drums to engage while driving. We put the timing back down to what it was originally my question is once the brakes engage like that is it permanent for one and two if let the car and the master cylinder will it be fine to drive the next day or does it have to be bleed again
 
Dominique Williams said:
Had my mechanic adjust the timing and distributor and the temperature got alittle bit hot in the engine bay that it heated up my master cylinder which cause my back drums to engage while driving. We put the timing back down to what it was originally my question is once the brakes engage like that is it permanent for one and two if let the car and the master cylinder will it be fine to drive the next day or does it have to be bleed again
Click to expand...

The engine running hot should not cause the brakes to self engage. If it is just the rear brakes that are locking up, check the park brake adjustment, the cables going to it and the rear wheel cylinders to be sure that they are not sticking. Has any recent brake work been done to this car? I suspect that if the master cylinder was replaced recently the travel rod adjustment from the brake booster is not adjusted properly. If the travel rod is too long, the master cylinder does fully return to the disengaged position and the brakes stay partially applied.

Dave
 
That's not a safe situation. If it gets hot enough to do that at home, just think what it would be like in traffic on a 95° day.
This sounds like a master cylinder that needs repair.
 
Davea Lux said:
The engine running hot should not cause the brakes to self engage. If it is just the rear brakes that are locking up, check the park brake adjustment, the cables going to it and the rear wheel cylinders to be sure that they are not sticking. Has any recent brake work been done to this car? I suspect that if the master cylinder was replaced recently the travel rod adjustment from the brake booster is not adjusted properly. If the travel rod is too long, the master cylinder does fully return to the disengaged position and the brakes stay partially applied. Dave
Click to expand...
I agree with Dave. A hot engine can't make the back brakes engage even though you don't have your foot on the brake pedal. I suspect the parking brake cables too. I've particularly had problems with the passenger side cable getting frozen in it's sleeve/guard and partially engaging that brake. If the car draws to the right when you do brake, check that passenger side first.
 
Dominique Williams said:
Had my mechanic adjust the timing and distributor and the temperature got alittle bit hot in the engine bay that it heated up my master cylinder which cause my back drums to engage while driving. We put the timing back down to what it was originally my question is once the brakes engage like that is it permanent for one and two if let the car and the master cylinder will it be fine to drive the next day or does it have to be bleed again
Click to expand...

In addition to the other points made here, check the adjustment of the rear shoes. They may be too tight. Did someone recently adjust them?
 
Like the guys are saying your rear brake problem has nothing to do with the engine bay heat. Rear brake sticking is usually residual pressure. The wrong or defective master cylinder or the rear brake hose is shot. Unless the hose is new install a new one its 25 bucks. Then work your way back to the master cylinder.
 
Not likely due to a hot engine bay. Do as advised in the other posts but I would also look for a leaking axle seal or brake wheel cylinder. Oil on the brakes will cause them to grab. Take the drums off and send us pics.
 
It's time to find another mechanic.

Buy a timing light along with some feeler gages and a dwell meter (if you have point ignition) and skip the mechanic for stuff that's easy to learn and do in your driveway. It will pay for itself the first time you don't have to pay someone. You can even do a conversion to electronic ignition (covered in many threads here) and skip the dwell meter purchase and never have to replace/adjust points again.

This stuff isn't rocket surgery. Watch some YouTube videos on the subject and after the first time you do it, you'll know as much as a lot of these guys here.

The only scenario that I can think of that would have engine heat affecting brakes would be if the brake line was too close to the exhaust. Any chance the car has headers? If that's the case, and the lines are close, you have to reroute the brake lines. BUT!!! If it's all stock, with stock exhaust manifolds and stock location brake lines, there's no way that would happen.
 
On a single master cyl, things rearward of the cylinder can be having some issues.

We once had a later model car come into the dealership. It had "locked-down" on the freeway while driving. Upon inspection, the diaphram on the cylinder top was massively expanded. The car had recently been to a fast-lube place for an oil change. Naturally, they topped-off the fluids, apparently putting the wrong fluid in the master cyl, which caused the massive swelling of the diaphram, self-applying the brakes until the car stopped. That one got a complete new brake system, per the fast-lube's insurance.

If the car started to run berter, which might also mean more toward "design temp" after the tuning tweaks, no real problem as the basic systems were designed for much higher heat ranges, I suspect, than what the car has been recently attaining. A little more heat would not be a significant situation, usually, even if some of the residuals accumulated on the exhaust pipes started to safeluy cook-off as a result. But DO ensure that no metal-metal contact happens between the brake lines/components and the heat-producing engine items. Should be plenty of air flow space.

Unfortunately, getting the issue diagnosed will take some time and efforts. A learning curve/experience, for sure. I concur with Big John on learning to do some of the more minor repairs, using YouTube and Chrysler MasterTech videos (www.mymopar.com) as learning guides. If you make some mistakes, you learn from them.

Enjoy!
CBODY67
 
CBODY67 said:
On a single master cyl, things rearward of the cylinder can be having some issues.

We once had a later model car come into the dealership. It had "locked-down" on the freeway while driving. Upon inspection, the diaphram on the cylinder top was massively expanded. The car had recently been to a fast-lube place for an oil change. Naturally, they topped-off the fluids, apparently putting the wrong fluid in the master cyl, which caused the massive swelling of the diaphram, self-applying the brakes until the car stopped. That one got a complete new brake system, per the fast-lube's insurance.

If the car started to run berter, which might also mean more toward "design temp" after the tuning tweaks, no real problem as the basic systems were designed for much higher heat ranges, I suspect, than what the car has been recently attaining. A little more heat would not be a significant situation, usually, even if some of the residuals accumulated on the exhaust pipes started to safeluy cook-off as a result. But DO ensure that no metal-metal contact happens between the brake lines/components and the heat-producing engine items. Should be plenty of air flow space.

Unfortunately, getting the issue diagnosed will take some time and efforts. A learning curve/experience, for sure. I concur with Big John on learning to do some of the more minor repairs, using YouTube and Chrysler MasterTech videos (www.mymopar.com) as learning guides. If you make some mistakes, you learn from them.

Enjoy!
CBODY67
Click to expand...
It was a single master cylinder but I swapped out that out for a dual and added a brake booster and a combination valve because it’s disc/drums now changed the hose in the rear even had new lines made its weird because everything was fine their was no noise or anything i had recently drove it home Friday from the exhaust shop no problems drove it again Saturday and then on Sunday he had adjusted the timing and the car got alittle hotter than usual and that’s when the squeaky started so now im wondering if everything is cooled down because i thought maybe the brake fluid had heated up and cause the rears to engage i was going to test drive it this morning to see if it was still doing it I work at a dodge dealership and was going to drive it in to get it looked at
 
Big_John said:
It's time to find another mechanic.

Buy a timing light along with some feeler gages and a dwell meter (if you have point ignition) and skip the mechanic for stuff that's easy to learn and do in your driveway. It will pay for itself the first time you don't have to pay someone. You can even do a conversion to electronic ignition (covered in many threads here) and skip the dwell meter purchase and never have to replace/adjust points again.

This stuff isn't rocket surgery. Watch some YouTube videos on the subject and after the first time you do it, you'll know as much as a lot of these guys here.

The only scenario that I can think of that would have engine heat affecting brakes would be if the brake line was too close to the exhaust. Any chance the car has headers? If that's the case, and the lines are close, you have to reroute the brake lines. BUT!!! If it's all stock, with stock exhaust manifolds and stock location brake lines, there's no way that would happen.
Click to expand...
It was a single master cylinder but I swapped out that out for a dual and added a brake booster and a combination valve because it’s disc/drums now changed the hose in the rear even had new lines made its weird because everything was fine their was no noise or anything i had recently drove it home Friday from the exhaust shop no problems drove it again Saturday and then on Sunday he had adjusted the timing and the car got alittle hotter than usual and that’s when the squeaky started so now im wondering if everything is cooled down because i thought maybe the brake fluid had heated up and cause the rears to engage i was going to test drive it this morning to see if it was still doing it I work at a dodge dealership and was going to drive it in to get it looked at
 
boltupal said:
Like the guys are saying your rear brake problem has nothing to do with the engine bay heat. Rear brake sticking is usually residual pressure. The wrong or defective master cylinder or the rear brake hose is shot. Unless the hose is new install a new one its 25 bucks. Then work your way back to the master cylinder.
Click to expand...
It was a single master cylinder but I swapped out that out for a dual and added a brake booster and a combination valve because it’s disc/drums now changed the hose in the rear even had new lines made its weird because everything was fine their was no noise or anything i had recently drove it home Friday from the exhaust shop no problems drove it again Saturday and then on Sunday he had adjusted the timing and the car got alittle hotter than usual and that’s when the squeaky started so now im wondering if everything is cooled down because i thought maybe the brake fluid had heated up and cause the rears to engage i was going to test drive it this morning to see if it was still doing it I work at a dodge dealership and was going to drive it in to get it looked at
 
Dominique Williams said:
It was a single master cylinder but I swapped out that out for a dual and added a brake booster and a combination valve because it’s disc/drums now changed the hose in the rear even had new lines made its weird because everything was fine their was no noise or anything i had recently drove it home Friday from the exhaust shop no problems drove it again Saturday and then on Sunday he had adjusted the timing and the car got alittle hotter than usual and that’s when the squeaky started so now im wondering if everything is cooled down because i thought maybe the brake fluid had heated up and cause the rears to engage i was going to test drive it this morning to see if it was still doing it I work at a dodge dealership and was going to drive it in to get it looked at
Click to expand...
The combination of new exhaust and new brake lines might cause the magic 8 ball to say "signs point to yes" for a problem of a brake line being too close. It's an easy thing to check, and something that is important to verify even if it's not the problem.
 
Big_John said:
The combination of new exhaust and new brake lines might cause the magic 8 ball to say "signs point to yes" for a problem of a brake line being too close. It's an easy thing to check, and something that is important to verify even if it's not the problem.
Click to expand...
Should I drive it to work today to check and see if everything is good since everything is cooled down he put the timing back to what it originally was where I didn’t have any problems or is it too late and im going to have to take the drums apart
 
When the rear brakes were self-applying, or appearing to do so, where was the brake fluid level in that portion of the master cyl? Just curious.

Thanks for the added information,
CBODY67
 
It was usually best to have the fluid level about 1/4" below the top edge of the reservoir, for general purposes. That way, when the top was removed, less possibility of brake fluid drops falling off and onto painted surfaces. No real concerns about fluid expansion or such, back then, unless fluid contamination might happen (which was rare).

I suspect that when fully diagnosed, you might realize how simple the issue might be and how easily it was to correct. Even if it might be a failed-new part.

Enjoy!
CBODY67
 
Dominique Williams said:
Should I drive it to work today to check and see if everything is good since everything is cooled down he put the timing back to what it originally was where I didn’t have any problems or is it too late and im going to have to take the drums apart
Click to expand...
Just open the hood and look at the level before you do anything.

I don't know how far you have to go or if the brakes are acting OK now, so I'm hesitant to say it's OK to drive.
 
Is the compensating port blocked???? Wrong pushrod length or setting?? Swapped parts can create a load of problems.
 
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