The previous ownerof my 1997 Jimmysomehow managed to put a big dent in the backing plate right at the wheel cylinder...the tab at the top, the one that all the springs connect to, broke off as well. I have another backing plate that I picked up today, so what would be the easiest way to go about doing this? My axle looks to have a couple bad seals anyway, so I'm thinking I should just do this theright way and replace the bad seals while it's apart...but how does it come apart? I believe you open up the diff, pull out the Clock and theaxle shaft shouldslide out, right?Also, how couldI replace the seal at theu-joint that connects to the driveshaft? Anyone attempted either of these jobs that can offer advice?


And one more question for someonewho might be knowledgable in the department, I picked up a starter and solenoind off a first gen V6, would it work with 4L60E? The trans did not look to be identical to mine, but it was cheap so I grabbed it regardless.

 

For the back plate, you have to remove the diff cover, remove the cross shaft retaining bolt, then the cross shaft. Push in on the axle and remove the c-clip, then remove the axle. While you are at it, you might want to assess the health of the outer wheel bearings. They aren't expensive, but the races can be a pain to replace.

The pinion seal... Now this may be possible by simply marking the axle nut, pinion shaft, and flange for alignment purposes. Also make note of the amount of thread which protrudes through the nut. Remove the nut, then remove the flange and replace the seal. Replace the seal. Reinstall the flange lining up the marks. Then tighten the nut ONLY until the marks line up with the required number of threads protruding.

 

Cool good advice. Another question, if I pull the cover off the master cylinder and step on the brake, is it normal for fluid to shoot up from one of the chambers? Is the one closest to the firewall for the rear brakes? I'm thinking when Iwentthrough a bed of rocks (more like boulders...ended up getting highcentered on one)I pinched aline somewhere...which is causing the fluid to come back through the lines and "shoot up" quite literally through the master cylinder. Thoughts?

 

I have experienced this on a few different occassions and never have really figured out what caused it. Everyone I have ever talked to said that it shouldn't be doing that, but all but one of the vehicles that did this had good braking. The one that wouldn't stop to save its life had MANY other issues and was sold before figuring out what the issue was (wasn't my vehicle).

How does the vehicle stop?

 

Well I know for sure that I currently don'thave any pressure to either side of the rear. I had the bleeder valves completely off and no pressure.

My rear brakes have never worked well enough to even stop the back tires at idle when jacked up...so I cannot gauge how well they work in comparison to how they should be working. After replacing the front rotors and pads I've actually noticed an improvement over what it was when first purchased. I replaced the master cylinder assuming that was the problem but it didn't fix the problem. It's gotta be adamaged line, no?

 

Sounds like the lines going to the back are pinched and not allowing fluid to go to the rear brakes at all I would trace all of your brake lines leading to the rear first and see if they are pinched!!! After that if none are pinched then there is something in the lines preventing fluid going to the rear brakes!!! What I would do is check the lines to see if any are pinched,if none are pinched I would then open the bleeder screws leaving the lid on the master cylinder and have someone press the brakes while your looking at the bleeder screws. Now if nothing comes out ( I think you have drums in the rear) I would suspect bad wheel cylinders that might be plugged up with something. So if this is the case I would either try cleaning them out or replacing them!!

 

More than likely the proportioning valve has failed on you. You can inspect for line damage easy enough. You may want to start with a good bench bleed of the master cylinder, then work from there.

 

Is the brake lite in the dash on? How many miles on the truck? On occasion, the rubber lines will fail internally, and will not allow fluid to flow. They look fine on the outside, maybe a little cracked from weather, (consider where they hang out....) Before spending money on parts you may, or may not need, find out where the problem is. Having a friend help with this makes life SO much easier. (and if you can get your girlfriend to help with it, so much the better. something you guys can do "together".....) Don't be surprised if she isn't interested though.

 

If you have no pressure to the rear brakes try opening a front bleeder and pushing the brake pedal to the floor. You should feel a pressure increase, then decrease (maybe even feel or hear a little click) as the proportioning valve re-sets. Then close off the front bleeder and try again to bleed the rears.

 

The Jimmy has about 140,000 miles on it. When my rear brakes used to work (poorly), I bled them and I was in factgetting pressure. When I pulled the drums off, I found that the dent in the backing plate caused the wheel cylinders' piston to be at an angle where it didn't push against the shoe...so it just popped off. Also a fluid, whether oil from the shaft seal or brake fluid from the wheel cylinder, had gotten all over the shoes, drum and everything else in there. This was on the right side...the left was a little better. I cleaned everything as best I could to get the fluid off, and put it all back together. When I drove it again, there was little improvement. Looking back, I think thepiston just popped off again.

At that time however, there was no brake light. Then a few weeks ago, when I went through that bed of rocks, I had gotten stuck and used the parking brake to try and get both tires spinning. Since then the instrument clusters'brake lighthas stayed on and the next time I checked the rears, they had no pressure.

I'll try bleeding the fronts to get the proportioning valve to resert. Where is it located? Is it prone to failure? I have checkedasmanyexposed brake lines as I could find, and they all look good...so I'm thinking this is a good diagnosis. What would replacing this valve consist of?