Hi All - '92 Ranger 2WD with 4 cyl and 9" brakes, right rear wheel cylinder keeps blowing out, replaced it twice. I've thought about maybe an obstruction in the left brake line creating too much pressure, or in the junction block on the rear axle. I believe only one line leads to there from the master cylinder, so what else could it be? Only other thing I can think of is that the right brake has a mechanical problem which is causing the forward shoe to move too far away from the cylinder, leaving no 'stop' so the piston just slides right out of the cylinder. But I can't figure that. Original adjuster star wheel was chewed up so I swapped in another, doubt it's that. Any ideas? Thanks,

92

 

Maybe the brake drum is too warn and basically too big so the wheel cylinder is pushing out too far. Nothing is going to cause too much pressure in the system to cause this.

 

Ck drum diameter as stated above . ck all hardware is intact and properly installed . Ck shoe adjustment and adjuster action . You stated you changed the star adjuster . Did you use the proper one ? Most are directional . Last off ck for gear oil contamination and frozen park brake systems . Gear oil can ruin a wheel cyl in short order .

 

Thanks for the responses, guys. Ok, I'll set aside the hydraulic approach and focus on mechanical. Well, the drum that was on there when I came along was beat up and grooved and ugly, so when I put it together the first time I put a wrecking yard unit drum there and adjusted it, I though pretty close to correct. Then when it failed again and I pulled it apart again that replacement drum was beat up the same way as the 1st one. So that makes me wonder.

I don't remember seeing any 90W oil anywhere; I assume that's what those differentials use? And that odor is unmistakeable, so I think I would have picked up on that. So I don't consider that one likely. I used mostly new hardware but the new starwheel came loose and when I put it together the 2nd time I used a wrecking yard unit. I was aware of the side-centric nature of those, as the parts place gave me the wrong side initially. So I thought that was squared away also. Guess I better buy another new one and make sure it's right side.

However, the comment about the parking brake does get my attention. I think I better get familiar with the setup there, try to figure out if it's way out of adjustment, and take a crack at adjusting it. I will also try to remove the left rear wheel and take a look in there; my Dad couldn't get that side off and I never did try, so I only did one side. --

92

 

If you do have gear oil contamination , ck axle condition . A worn axle and , or bearing can cause brake alignment issues .

 

Did the cylinder blow out problem begin After you replaced the adjuster????

 

JWC 3 - ok, I'll take a close look for 90W in there. Pawpaw - no, the wheel cylinder issue has been present all along; the truck was spewing fluid before I did anything, and when I tore it down I saw that the cylinder had come apart, the adjuster was all chewed up and pieces of shoe were loose, a real mess in there. Thanks guys,

92

 

OK good feedback, so the problem was there before Any work was done. SO, are you just doing a repair on the wheel cylinder, or are you replacing the entire cylinder with a new one & its still blowing out????

 

Pawpaw - I've relaced the cylinder each time with a new one from AutoZone. I haven't, and won't, go inside one of those since they're so inexpensive now,

92

 

Typo, meant 'replaced'...

92

 

OK, more good feedback, your replacing the wheel cylinder with a new one, so that sorta leaves you looking at a mechanical problem thats allowing the brake cyl piston to mechanically move beyond that for which it was deaigned, as has been suggested.

All that said, seems to me what remains, is the wheel cyl, brake shoe harware, or the brake drum dimensions being wrong, or some combination there-of, being wrongly matched!!!!

Probably a good idea to have a look at the other rear wheel, to see how its assy hdw looks.

 

Pawpaw - yup, I'll take it apart again tomorrow if weather permits, and start with the left side. What a trip it would be to find that the left is 10"...that would explain a lot! But I want to look closely at the e-brake, see if it's jacked up somehow,

92

 

OK, keep us posted on what you find.

 

Take a close look ranger , compare both sides . measure shoe and drums both sides . Ck hardware is all there ,and installed correctly . Hope you solve it soon . Ck adjustment ,that has a lot to do with cyl travel . One more thing , make sure your other side rear brake is working ! I always replace wheel cyl's in pairs . Hydrolics need to be the same or the weaker will fail in short order .

 

One more thing, I have seen park cables stick. That will hold the brake on and cook the shoes and wheel cyl ! A friend of mine drove 5 miles with his park brake on and cooked both wheel cyl !Not to mention shoes and drums , and a broken spring .