Brake emergency

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gdizzle

gdizzle

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Alright, just spent 2 days with my elderly father-in-law, he was a brake installer for 30 years, years ago. He was excited to help me replace all the brakes in my 1966 dart, 270, 225, L6. 9in brakes.

I gathered up all the parts, we ended up not completely replacing everything.

Front wheels got repacked, new bearings, new seal etc... one front wheel got a new cylinder. all new shoes, new adjusting sets (try tracking those down). The one front wheel that got a new cylinder, also got bled. No other wheels got bled.
Front brakes work great.

Rear: all new shoes etc..., cylinders appeared ok so kept them. One rotor was bad, but the other was good.
Installed and adjusted. Engaging the EBrake seemed to cause issue, wouldnt release etc... I worked on the cable, let it out a little, cleaned up the grungy mount parts. Seems to slide in/out better.
The driver side rear wheel is screwy. Parking brake is off. I start the car, put foot on brake, shift into D and I feel the pedal release a little. Let foot off brake and Left rear wheel begins to spin, then I brake normally, wheel comes to a stop, but then I release brake and the wheel remains stopped, I press brake, wheel spins, release brake wheel stops. The Right rear works as normal, although doesnt really come to a complete stop, But I think that just needs some adjusting.

Curiously, I removed tire and drum on the driver rear, and (engine off) slowly apply brake and the cylinder is very slow to react, and when it does it is the Left piston. The right one doesnt really move, until after a few times.

So now I either think the wheel cylinder is bad , or there is a bunch of air in the system that is displacing the fluid, causing the other tires to pull all of the fluid leaving none for the driver rear? Does that make any sense?

Help and any thoughts?
 
Sounds like you have a bubble and a bad wheel cylinder. Make sure there are no dings in the steel lines also.
 
gdizzle said:
Front wheels got repacked, new bearings, new seal etc... one front wheel got a new cylinder. all new shoes, new adjusting sets (try tracking those down). The one front wheel that got a new cylinder, also got bled. No other wheels got bled.
Front brakes work great.
Click to expand...

Doesn't a 66 have a MC with only one reservoir? If so, you introduced air into the system when you changed the wheel cylinder.

Bleed the whole system, left rear, right rear, left front, right front, in that order.
 
One of the ways I have been able to cheat on bleeding brakes by myself. Remove and clean bleed screws with wire wheel and drill bits. Let system gravity bleed closing each screw as the fluid runs out. With all bleeds tight loosen the closest to the master cylinder and then make it finger tight only. Pump your brakes till you get a good pedal and hold for a few seconds. The pedal may drop slightly. Release the pedal tighten the bleed screw and move to the next closest wheel. The finger tight bleed screw acts as a check valve and will release air easily but not so much with the fluid.
 
I meant to put a picture in. just for brakes sake. Yes this is single chamber master cyl. We were real careful not to get air in, he has a special tool that keeps the pistons closed. But I am thinking maybe air was already in the brakes. I hope that wheel cylinder isnt bad. hate to remove everything again. dealing with those springs and cable and pivot point and the f'ing parking break bar, not fun.

I think bleed the whole thing, and see what happens. I read you have to adjust all brakes till they lock the wheel, then bleed? Do I really have to do that? I dont want to have to readjust all of them again. even though he has all the tools, very painful to watch him do it. shaking hands and all bless his heart.
 

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Tough read. The differential will turn the wheel that turns easiest. So let of the pedal means other turns and this one stops. Press the pedal and other stops so this one turns. press pedal hard enough both stop ? You probably should bleed the entire system but... I don't think you'll get exactly equal drag left and right, simultaneous, from a open differential while up on stands.
 
Air in the system especially a "single" MC system is NOT going to cause different pressures through the system. Air IS going to cause a low, spongy pedal. I didn't notice you mentioned that? Pedal high? Hard? (A low hard pedal is usually shoe adjustment)

Another probem MANY guys miss, not being used to drums, is the SIZE of the drums due to wear or "turning" If a drum is turned or worn very far larger than "standard," the shoe fits inside the drum "in the center" that is the shoe does not have much contact. This reduces the braking area. You can have a nice hard pedal, but very poor braking with this condition.

I'm not sure what your problem is.......have you tried to adjust the shoes and drive the car? ALL shoes must "seat" for a short drive.
 
What you are describing is common of a non-sure grip axle the easier wheel will spin and sometimes both. If you adjust the right wheel and it still does not stop when applying the brake you may have a bad hose at the rear axle as I have seen that a few times.
 
Ima calling it a bad wheel cylinder.
But just to be sure disconnect the self-adjuster cable and apply the brake again. If the one piston is still lazy, I think that confirms it.
What I cant figure out is why, if you opened the system to replace one WC, you didnt pop them all open for inspection. I have a feeling you would have replaced the rest of them too. For what they're worth I would have,or,at least honed them and kitted them.
All the best to you
 
I was thinking the same thing.

I had one in the shop that did the very same thing, on a front disc. A hard stab, and it wouldnt release. A second softer,slower application, and it reverted to normal.
Its hard to imagine this on the rear though where there are two brake cylinders on the same flex-hose.

Just curious, did you polish off the rust on the shoe,bearing pads?
 
AJ/FormS said:
Ima calling it a bad wheel cylinder.
But just to be sure disconnect the self-adjuster cable and apply the brake again. If the one piston is still lazy, I think that confirms it.
What I cant figure out is why, if you opened the system to replace one WC, you didnt pop them all open for inspection. I have a feeling you would have replaced the rest of them too. For what they're worth I would have,or,at least honed them and kitted them.
All the best to you
Click to expand...

SGBARRACUDA said:
A bad, collapsing brake hose can cause a brake not to release also.
Click to expand...

AJ/FormS said:
I was thinking the same thing.

I had one in the shop that did the very same thing, on a front disc. A hard stab, and it wouldnt release. A second softer.slower appication, and it reverted to normal.
Its hard to imagine this on the rear though where there are two brake cylinders on the same flex-hose.

Just curious , did you polish off the rust on the shoe,bearing pads?
Click to expand...

Ditto? Tritto?
 
Bled it..mostly. When I got to the last wheel (Right Front), the little bleed screw was smaller than the others (smaller than 1/4) and stripped. Impossible for me to get at it. I didnt see any bubbles anywhere while I was bleeding.

Tried another test up on stands. Still same, back left wheel would not spin when brake was off, but would spin when brake pedal was down, but if I really pushed hard all the way down, it would start to slow the wheel.

Took it off stands, drove a little, doesnt feel like it is dragging. But man it is hard to stop. Impossible to get it to lock up.

Taking it in for shop to adjust and inspect. thanks for all your help
 
AJ/FormS said:
I was thinking the same thing.

I had one in the shop that did the very same thing, on a front disc. A hard stab, and it wouldnt release. A second softer,slower application, and it reverted to normal.
Its hard to imagine this on the rear though where there are two brake cylinders on the same flex-hose.

Just curious, did you polish off the rust on the shoe,bearing pads?
Click to expand...

I have seen the rear hose cause trouble that is why I mentioned it. The last one I had that was bad I could not bleed it because it would not allow fluid through.
 
fluid came out the back when I bled it. I think hoses are good. However I do see that the front rubber hoses are nicked up pretty good from hitting this little L shaped guard? not sure what that is for.
What does Polishing rust off shoes mean? All shoes were brand new. 1 rotor was brand new. the other 3 rotors looked ok. hit everything with that CRC brake cleaner stuff.

Anyone else have a problem with ordering wheel cylinders from Oreilly? Online said all 4 wheels use same cylinder. When in reality the front wheels actually take a different size altogether. That was a pain to track down.
 
gdizzle said:
. But man it is hard to stop. Impossible to get it to lock up.
Click to expand...

This is at least one symptom of oversized drums with non arced shoes, or drums in bad condition. I mentioned this before?
 
You cannot afford to "think" your hoses are ok!
Ok. I think that you dont understand about flex hoses and how they go bad. They may look fine on the outside. But they rot from the inside, out. What often happens, is the brake fluid goes out to the WC but on its way back, it seems to slam a rotted rubber flapper down to act as a checkvalve. Sometimes it bleeds back to the M/C: It might take a minute or an hour or overnight. Sometimes a soft apply and a gentle release, will shuttle the checkvalve, and allow the fluid to return.
If you cant say that the hoses have been replaced in the last 3 to 5 years, I would strongly, VERY strongly, urge you to replace them on your SINGLE chambered system. If any single hose fails on your system, you are in the wall!
When you put new shoes in there, the W/C cups/pistons/pushrods all have to be pushed back into their bores; usually right on top of where the rust accumulates. Shortly afterwards, they leak. All over your brand new shoes. The W/Cs should,at the very least,all be opened up and inspected. If any single cup turns sideways in its bore,because it stuck on some rust on its way back, you are in the wall!
There are no places to cut corners, on a single chambered system.
The 9 inch system is marginal at best.
Do it right or pay someone to do it right.
I am not being an a$$. Your life, and the lives of everyone around your car may depend on all 4 of those Wheel cylinders doing their jobs.You cannot afford even just one piece failing.
 
Good grief. Some posts read like these brake systems should never have been allowed on the streets. The car is what 50 years old ? over 100K miles ? and hasn't hit a wall ? Some luck huh ?
If you are resurrecting the dead, of course you should replace 100% of the brake system. Routine maintenance is just what you've done, inspect carefully, service/repair/replace as deemed necessary.
From what I've read, these modern model hoses with metal straps crimped onto them have a higher failure rate.
 
RedFish said:
Good grief. Some posts read like these brake systems should never have been allowed on the streets. The car is what 50 years old ? over 100K miles ? and hasn't hit a wall ? Some luck huh ?
If you are resurrecting the dead, of course you should replace 100% of the brake system. Routine maintenance is just what you've done, inspect carefully, service/repair/replace as deemed necessary.
From what I've read, these modern model hoses with metal straps crimped onto them have a higher failure rate.
Click to expand...

Your right, The late model Chevy trucks that had the metal mounting bracket crimped around the front brake hoses were notorious for collapsing right at the crimp. I have replace many of them in the past.
 
did you check the wheel cylinders in the rear by stroking the pistons back and forth to see if they move freely? This will indicate if one is sticky or not. I always cycle the wheel cylinder pistons with the rod in them from side to side to make sure that they move freely.

If they pass the "feel" test. then I would re bleed and go from there...


Did you grease the backing plates on the three flat spots where the shoes ride/contact? The shoes need to be able to move freely...
 
gdizzle said:
fluid came out the back when I bled it. I think hoses are good. However I do see that the front rubber hoses are nicked up pretty good from hitting this little L shaped guard? not sure what that is for.
What does Polishing rust off shoes mean? All shoes were brand new. 1 rotor was brand new. the other 3 rotors looked ok. hit everything with that CRC brake cleaner stuff.

Anyone else have a problem with ordering wheel cylinders from Oreilly? Online said all 4 wheels use same cylinder. When in reality the front wheels actually take a different size altogether. That was a pain to track down.
Click to expand...


The rears take the same wheel cylinder as the bleed screw comes straight out.

The fronts take a different cylinder for each side as the bleed screws are angled.

Most of today's parts guys don't know this... #-o
 
RedFish said:
Good grief. Some posts read like these brake systems should never have been allowed on the streets. The car is what 50 years old ? over 100K miles ? and hasn't hit a wall ? Some luck huh ?
If you are resurrecting the dead, of course you should replace 100% of the brake system. Routine maintenance is just what you've done, inspect carefully, service/repair/replace as deemed necessary.
From what I've read, these modern model hoses with metal straps crimped onto them have a higher failure rate.
Click to expand...

Not some luck, but you just pointed right at the problem. The car IS 50 years old with over 100K miles. That's well beyond the service life of the rubber items in that brake system. For that matter, the hardlines should be inspected closely. Keep in mind, brake fluid sucks up moisture like a drunk at an open bar, so the insides of those lines could be worse than the outside.

I won't go as far as saying that a stock 9" drum brake system shouldn't have been allowed on the street then, but with the average 200 dollar import beater being able to stop three times better on bad tires now, it is something to consider.

We now return you to your regularly scheduled brake analysis.
 
"What does Polishing rust off shoes (bearing pads) mean? "
The places where the shoes touch the backing plates after they have been mounted, are little bearing pads. Over the years,those pads get worn by the constant scrubbing of the brakeshoes. If the car sits for long periods of time, those pads rust up. These two conditions lead to brakeshoes not returning properly. Those pads need to have the rust wire-wheeled off, and the bearing pads inspected. Sometimes I have had to hard-braze them up and level them off with a grinder.

I'm a little confused;
In post #1, you say "the front brakes work great". Then
in post #15, you say " But man it is hard to stop. Impossible to get it to lock up. "

I'd say your brakes work like Cr.....
 
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