'89 XJ, D35 w/ drums.

I left work and as I tapped the brakes, my right rear wheel locked and my Jeep jolted to a stop. Happened 3 times on semi-wet pavement. This was tapping the brakes, not slamming them. I pulled over and couldn't see anything wrong with my brake lines, my fluid was full needs to be changed though. I left from there just hoping for the best and it didn't happy again. Broke open the drums when I got home and cleaned out a crap load of dirt, though.

Completely confused on this.

 

My guess would be that the pistons inside your brake cylinders aren't retracting fully . Moisture in the brake fluid tends to cause them to rust and then bind in the bore. I would pull both cylinders and either rebuild them (about $8 each so cheaper than replacing but a lot more work) or replace them (about $20 each but much faster).

 

Along with this, do you have a different size tire on the back? Tires of different brands though they are the same size on the label can be up to 1.5 inches different in height, this will cause wheel lock-up. Also one side of your brakes could be adjusted tighter than the other side.

 

OP states rear brake is locking up. Unless he converted to a disc brake system for the rears, I'd say there is no pistons in there, just wheel cylinders and springs to get the shoes back in position.

When was the last time the rears had a service?

 

Unevenly worn pads can cause the same thing if one side is worn out.

 

There are pistons. In fact, there are two of them per cylinder... little tiny ones about as big around as your finger. They're horizontally opposed (like the pistons in a boxer engine) and pressed out of the cylinder under hydraulic pressure to move the brake shoes against the drum, the springs bring the shoes back to their resting position. Those little pistons are just as prone to seizing as the big pistons in the front calipers and we all know that's not uncommon in XJs.

 

Didnt realise that they had the capability to seize like their big brothers in front. Thanks for this.

 

possibly start with a brake shoe clean and adjust and see if the problem comes back

 

This requires an inspection and removal of the brake drum.

Could be brake fluid or axle lube on the shoes, wheel cylinder issues as stated, brake shoe hardware coming apart, shoes disintegrating. The list goes on and on.

Time to get your hands dirty.

 

That makes sense. I do live on the wet side of WA State, and my brake fluid is slightly rusty.

Same size, same brand. Mostly even wear.


I adjusted them doing the screwdriver trick on the star type adjuster on the backside a month or so ago, no problems routing from that. The shoes and drum cover weren't bad so I haven't changed the shoes yet.


I've opened them both up and blew out a lot of dirt from all over inside. There was nothing wet inside, but I'm not sure about the interior of the wheel cylinders. I'll buy new shoes, fluid and cylinders this weekend. It needs it anyway.

 

Bleed the crap out of the system. Actually remove the fluid from the master cylinder with a turkey baster first. Then put new fluid . Then bleed.

Since it's so close to Thanksgiving, don't use the baster form the kitchen.

 

That was the plan.



Oh

 

" Cruiser54: For all your Renix & Gourmet Advice " ...

Thats why I like you so much mate, you never loose sight of the bigger picture

 

A little "Renix on the barby"?

That's what happens when you leave the stock injectors in!!!

 

I'm sure I would have still had my 89 Wagoneer if I had discovered Cruiser 54 a few years earlier....Gold with fake wood panels, stacked double headlights...Rest in peace.