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Brakes-Drivers side caliper trashed

2K views 17 replies 4 participants last post by  Aggiesrok 
#1 ·
I had an occasional knock sound when in reverse and stopping on drivers side. Recently it started to lock up the left brake in reverse, but forward was always fine. Nothing was seemed loose, adjusted the tie rod end slightly (tiny bit of play) and the steering box, then went for a test drive in a parking lot.
Locked up in reverse, drivers side, then moving forward it would release. Reverse no gas or brake and after 10 feet it would lock up. It started to make more noise and grinding sounds, so I decided to head home, only 1/2 mile away.
While driving home, huge knock-clunk sound and look back and the whole caliper assembly is in the middle of the street. Made it home, but the dust cover, caliper, bracket, hose, etc are trashed. Both of the caliper bolts sheared off in the mounting bracket.
The MC and Booster, calipers, rotors, wheel bearings were replaced within the last 18 months. The rears are drum and rebuilt about 2 years ago. Everything was torqued to spec with a torque wrench. I suspect the caliper brackets were rusty in the threads and didn't allow to tighten down before reaching proper torque setting. I'll take some pictures as I disassemble tonight or tomorrow.
It may have trashed the spindle, not sure yet. You can't buy 67 spindles new, they sell 70-73 spindles new and you must use 68 brakes with 70 tie rod ends. Does anyone know if this is a good setup and what else needs to change, rotors? I can't replace the whole thing. Thanks.:banghead:
 
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#2 ·
Torque specs are for new threads with oil... on brake parts (safety parts) always use thread locker!

An idea of what broke first?
what's your brake stuff brand?
 
#3 ·
I did apply oil before installation, I was thinking that there was an obstruction from past rust in the bracket or maybe I didn't get enough oil in it.
I suspect one of the bolts broke first and the other held on as long as possible, but I don't really know. It just seems like with one bolt broken, it would allow the caliper to move a little when in reverse and eventually led to it locking, then unlocking when moving forward. The extra stress I put it through, finished the other one off.
They were brand new caliper assemblies from Dallas Mustang, but I don't think the calipers actually failed. I don't really know what's been done to this car and I've just been fixing stuff as it breaks over the past 3 years.
 
#4 ·
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Chevy runs deep, don't step in Chevy.
 
#5 ·
Anyone know why Ford changed in 68-73 to a single piston caliper? Were the 65-67 4 piston calipers sticking or applying unequal pressure?
 
#6 ·
The reason Ford changed was "economy of scale" along with maintenance. From 68 and up they went to a floating caliper instead of fixed.
The 4 piston does exert force on the pad/rotor more evenly than a single piston and the 4 piston has more moving parts that can require maintenance...plus the single piston is cheaper to manufacture.
One thing to keep in mind when replacing worn or broken parts is the hardware, espcially chassis hardward. Having this used hardware and not knowing how many times it's been over torqued or under torqued is the question...also trusting 49 year old hardware to hold together critical parts....well....they should have been replaced when the calipers were replaced....IMHO
 
#7 ·
Thanks for the response. I kinda figured it was a cost reduction, but seems strange that they can get the same brake force.

But anyway, now I really need some HELP.

I replaced the caliper brackets on both sides as well as the hardware and brake lines. I installed a brand new caliper assembly on the drivers side. I bled the pass. side, no problem. I then tried to bleed the drivers side and never got any brake fluid to come out.
I was using a pressure bleeder, never went over 15 psi. So then I reverting to old school with my son pumping the brake pedal. Still no fluid from bleeder screw.
I put a vacuum hand pump on the bleeder valve and it will not hold a vacuum. My son pumped more and then the pedal went all the way to the floor and now there is no resistance at all.
So I'm afraid it's somehow messed up the master cylinder.

Any ideas would be greatly appreciated. :banghead:
 
#10 ·
Was able to sorta bleed the master cylinder. The plastic adaptor for the fronts was leaking a little, but I was able to get a little more pedal pressure and fluid is flowing in both. So I'll pick up new ones tomorrow and get a get MC bleed and hopefully get the pedal pressure back.


Chevy runs deep, don't step in Chevy.
 
#12 ·
For bench bleeding the MC. They screw in and have hose tips so you can feed the fluid right back into the reservoirs.


Chevy runs deep, don't step in Chevy.
 
#13 ·
Ok went with a new master cylinder. In the process of removing the old one I discovered this bent rod at the brake pedal.
I'm not sure I'm comfortable with only replacing the rod, if it bent from normal use. Is the rest of the booster a POS also?
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Chevy runs deep, don't step in Chevy.
 
#14 ·
I am surprised that it didn't damage the master cylinder bore or seal on the piston.
How did you bend it like that...do you have a size 22 right shoe????
You know on second thought I wonder if you had a hydraulic lock in the line and pushed so hard with the size 22 shoe you bent the rod....
 
#15 ·
I did find out some new information. Apparently the 67 brake pedal is a little different on an all drum car w/o booster. The push rod location is different and would have caused the rod to be at an angle.
I don't know exactly what was originally on the car, only had it 3 yrs.
but this is the only thing that makes sense, even a size 22 should not bend that. Lol. I've found all kinds of crazy stuff on this car, so a bad disc upgrade is no surprise.
Yes the MC is messed up. So getting a kit that has the correct pedal and a new MC/Booster combo.


Chevy runs deep, don't step in Chevy.
 
#16 ·
Well, if anyone's interested, I got the brakes fixed. In the end I replaced LH caliper, LH brake hose, both rotors (already turned), both caliper brackets, LH splash shield, Master cylinder, Brake Booster, Brake pedal, 2 brake lines and the distribution block. So far everything seems to be great.
I replaced the stock distribution block with one pictured below, that I got from Jegs. It's really a great option. It has a built pressure switch for the brake lights and the built in proportioning adjustment. It's machined from solid aluminum and black anodized. I was having trouble getting the brake light switch to work and instead of grinding and shimming, I decided to go with this. It's a lot cleaner and looks great without having to worry about the brake lights working.
Anyway thanks for the comments and hope to have these issues behind me, it's a challenge working behind someone else's repairs.



 
#18 ·
No, I'm up in East Texas for work. Sorry.
 
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