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best way to repair/remedy frozen brake

best way to repair/remedy frozen brake

smbundy13

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Location
Texas
Vehicle(s)
1980 CJ7, 258 I6, SR4, D300. Power steering, power brakes. Stock axles stock susp. Gentle rehab in progress.
I finally drove my CJ out of the shop this weekend.. only to find that I have a frozen brake. The jeep can barely move.. I wasnt trying to drive on the street, its not ready for that yet. I was trying to get some tire sealant spread around my temporary tires..

I am not sure which is frozen.. I am certain all need to be addressed. first, how can i figure out which brake is frozen? simply jack each corner up and try to spin by hand? how much resistance is too much?

how can I free the brake?

thanks.
 
I was going to suggest the method you described. Jack up each and try to spin them. They should spin freely. You should find the frozen one (or more) quickly that way.

And how to free it up depends on disc or drum. But depending on how much you want to reuse, I would try to remove the calipers (if disc) and use a mallet to move the caliper off of the rotor.

If Drum, one the wheel is off the mallet may be the only way to free the drum.
 
If you have a frozen front caliper, it is possible that a flexible brake line has collapsed on the inside. This would require replacement.
 
Are YOU sure it's the brakes?

LG
 
Are YOU sure it's the brakes?



LG



Agreed. Jack up front and year and see if the wheels spin. See if the brakes are actually pressing the rotor and/or drums. It would suck for it to be in one of the axles. Start diagnosing and let us know what you are finding out.

Pictures help us internet mechanics too.
 
IF you are sure it's the brakes. Open the bleed screw on each wheel.
If you can now move the Jeep, you have either a bad MC or proportioning valve along with calipers and wheel cyl.
BE CAREFUL as you will have NO BRAKES with the bleed screws open :eek:
:chug:
LG
 
IF you are sure it's the brakes. Open the bleed screw on each wheel.
If you can now move the Jeep, you have either a bad MC or proportioning valve along with calipers and wheel cyl.
BE CAREFUL as you will have NO BRAKES with the bleed screws open :eek:
:chug:
LG

thanks. i will try that. will post my results..

thanks everyone for the ideas.
 
finally was able to take some time to check my jeep's brakes. both front disc brakes seem to be frozen. was thinking about how to best free them up. i want to take the calipers off and inspect them. I know i will be replacing the front brakes soon but not now so i dont want to buy new calipers and not rotors etc.

so, are there any ideas on how best to free up the caliper? i opened the bleeder valves on each caliper and fluid move out.

can i take the calipers off and press the pistons back in? (if they arent rusted, which they prob are)

if I do end up replacing the brakes, it looks liek i will need to basically pull each corner's hub and rotor assembly off. is that correct? if I do that, i would like to get some long wheel studs as the current ones are way short.. like barely flush with outside of a lugnut short. any suggestions?

I havent checked the rear brakes yet since I usually only have 30-60 minutes in the shop at a time nowadays.

thanks alot.
 
Use a large "C" clamp. Put the stationary end of the clamp against the back of the caliper, and the screw end on the outer pad and tighten the clamp. The fluid will just move back into the master cylinder. Once you get them apart, I would change all the brake fluid.
As for the wheel studs, are your wheels thicker than stock? No reason that stock studs should not work. Generally, wheel spacer manufacturers want you to have a minimum of 8 turns on the lug nuts. I just put 1 1/2" spacers on my 79 CJ7 and had to use slightly longer studs. I think that the stock studs are around 1.6". I got 2" studs that pressed right in at Advance Auto. https://shop.advanceautoparts.com/p...YSXeU9GUftdtzQg5gI6l9oYYdkuiz3UKvVSbo9GJMf6Ys
 
I can also use that link, as I have aluminum wheels that make the oem studs a bit short. Thanks Bass
 
You are quite welcome! No one that I called was able to look up studs based on dimensions. I literally had to look through over 60 pages on several parts house web sites then make sure that all dimensions were correct to find the right ones!
 
was able to work a little yesterday afternoon. I tried compressing the piston back into the caliber a bit and it freed up both front hubs.. but, the first time the brakes were hit the pistons went out and stayed out and locked up again. I am going to buy new calipers today. have found some from Napa for about $25 a piece, no including core.

not going to do the whole front end refurb yet since the jeep is a ways from being driven on the road.

I think i am going to buy new brake lines as well.. just factory replacements.. they are about $15 per.

so, new calipers and brake lines for now. I know I will need to do new rotors and pads etc.. just dont have the $ to expend right now.
 
If both of your front brakes lock up like that. I would be replacing the master cyl, not the calipers.
LG
 
If both of your front brakes lock up like that. I would be replacing the master cyl, not the calipers.
LG

possibly, but I am going to try the calipers first. at $25 a piece, they are cheaper than any master cylinder i have seen.
 
got the calipers replaced last weekend. still need to bleed the system. I couldnt find my brake fluid so will need to buy some more.

I bought new front lines but couldnt figure out how to get them off at the frame side so i rolled with the originals. the calipers were definitely frozen! one didnt move at all with compressed air and the other took a lot of pressure to move.

a couple of things I noticed/learned on this.
- on the '80, i only had to take the retaining clip thing off to slide caliper off (learned that after taking off the whole works with the first one)
- turning the wheels without the engine running caused my power steering pump to leak fluid. I could hear the pressure everytime i turned the wheel. I know i need to replace the box as it is leaking.. might replace pump at the same time.
- also, found a small fuel leak on the fuel return line at the function of the hard line and rubber line right off the block. but, when i started the jeep, the leak stopped and didnt continue. I will investigate further next time i am in the shop.

so, next question is the best manner of bleeding my brakes.. I keep reading about the proportion valve retainer tool that is required or i will trip the valve? also read about gravity bleeding..

what are yalls recommendations?

thanks very much.
 
You can use a brake bleeder pump which attaches to each brake cylinder bleeder. Fill the MC, crack the wheel cylinder and pump. The old fluid will collect in the bleeders reservoir.
Or, you can do it the old fashioned way. Fill the MC, then have an assistant pump the brake pedal 3 or 4 times. Then have them hold the pedal down while you open the wheel cylinder. Have them hold the pedal down until you close the bleeder, then repeat the process until the fluid runs clear, and there are no more air bubbles in the line. Then move on to the next wheel. I like to start with the wheel furthest from the MC, and work toward the closet. In other words, RR, then LR, then RF, then LF.
Remember to watch the MC fluid level. Don't let it drop so far as to allow air to enter the line or you will have to start all over! Also, set the cover back on the MC each time the pedal is pumped, or you will have a geyser of brake fluid squirting straight up!
I have never had any problems with OEM or after market proportioning valves using either of these methods.
 
You can use a brake bleeder pump which attaches to each brake cylinder bleeder. Fill the MC, crack the wheel cylinder and pump. The old fluid will collect in the bleeders reservoir.
Or, you can do it the old fashioned way. Fill the MC, then have an assistant pump the brake pedal 3 or 4 times. Then have them hold the pedal down while you open the wheel cylinder. Have them hold the pedal down until you close the bleeder, then repeat the process until the fluid runs clear, and there are no more air bubbles in the line. Then move on to the next wheel. I like to start with the wheel furthest from the MC, and work toward the closet. In other words, RR, then LR, then RF, then LF.
Remember to watch the MC fluid level. Don't let it drop so far as to allow air to enter the line or you will have to start all over! Also, set the cover back on the MC each time the pedal is pumped, or you will have a geyser of brake fluid squirting straight up!
I have never had any problems with OEM or after market proportioning valves using either of these methods.

thanks for the info. i have bled a brake system before but the proportion valve tool kept creeping up in my reading.

if it is tripped, is there a way to reset it? (the valve)
 
I have never heard of "tripping" the proportioning valve. Doesn't mean that it's not possible, but I have always bleed the system as I stated above with no ill effects to the proportioning valve.
Here are a few other discussions pertaining to, and basically stating the same thing.
http://www.jeep-cj.com/forums/f19/what-proper-way-12118/

https://www.jeep-cj.com/forums/f2/brake-bleeding-proportioning-valve-16161/

thanks alot. i will just roll with bleeding the system as normal then.
do you have any recommendations for a vacuum bleeder?
 

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