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Being that the 91 Suburban is a square body I posted here in hopes of getting some help.
I have a 4x4 suburban 1/2 ton I just overhauled the brakes. On the back brakes I replaced everything (All springs, axle brake lines, wheel cylinder, all new hardware including self adjustment wheel and kit and the wheel cylinder links) except the drums and the backing plate which I couldn't find a new replacement.
Please note also there is no parking brake cable at all, no parking brake strut or the arm that holds the cable.
Three things I have done that could have contributed to the problem that I want to mention.
1.) The only replacement wheel cylinder links I could find were slightly longer. (The original ones were terribly rusted and there was no drag what so ever.)
2.) I cheaped out and didn't get the rotors turned. They looked fine.
3.) The backing plate tabs had grooves in them so I carefully ground them nearly flat as to not take an insane amount of material off.
So I put everything together and adjusted the star wheel to where the pads were just barely touching the drums. With the wheel off, the drum did spin nice and freely. Though I suspect slight warpage.
I drove to town about 7 miles away and back and everything seemed normal. Got out of the truck and smelled a burning smell and noticed the hub on the driver's side rear wheel was too hot to touch.
I jacked the truck up and the wheel could spin freely by hand going backwards, but forward it would lock up!
I took the tire and drum off and backed off the adjustment some, put it back together and once again it moved forward and backwards freely. Took it for another test drive and the same thing.
I have ordered another set of pads because the ones I put on are heat damaged and ordered a new set of drums.
I just can't figure out why they would lock up going forward and not in reverse.
I'm just fishing for ideas here, never seen anything like it.
(Update): I lightly sanded the brake shoes and they look good as new. I got the rear end jacked up and backed the star wheels all the way to the closed position.
With the drum off on the driver's side, I lightly pressed on the brake and the rear shoe was failing to return to a closed position. I added extra lube and it appears to be functioning. But I still don't feel confident the problem won't return.
Anyhow, I'm incrementally adjusting the star wheel by 50 clicks on each side and with the truck in neutral the wheels turn and I work the brakes. Put it in drive and reverse working the brakes. So far so good. Now making smaller increments in adjustments.
If anyone knows where I can find brand new backing plates and the proper wheel cylinder links it would be much appreciated. I can't find them. I even called Dorman and they have nothing. It's a 91 ten bolt, 30 spline, 6 lug axle.
I found a disc brake kit for around 400 bucks, but I feared having to change out the proportioning valve and master cylinder. I don't know that I would, but am afraid to open that can of worms. Unless someone has did a rear disc conversion and can tell me otherwise.
I'm just wanting my brakes to work properly. It's a rusty old truck that's my daily driver.
By Ramblin Man
Last summer I purchased a 2001 Yukon XL with the 5.3L engine, replaced the rear rotor/pads and air filter, then went on a 13,000 mile 8-month road trip starting in Boston, going through Maine, Atlantic Canada, back to Boston for a seasonable job, then to New Mexico via South, back again to Boston through the midwest and finally Florida to help my folks through covid (all safe).
The truck now has 191K miles, but the original title indicated the mileage was not accurate (which is how I got it for $1,200 on eBay), so, who knows. The mechanic who did the rear brakes was surprised how little rust was in the undercarriage. I removed the rear seats, added a mattress and three milkcrates for my stuff, installed a cheap aftermarket radio with bluetooth and a rearview mirror camera. Brake and ABS warning lights were skillfully covered with duct tape by the previous owner, I removed the ABS fuse because ABS kicked in without need when breaking at low speeds (dirty sensors?).
Over the 13K miles I had 2 oil changes + tire rotation at Wally, and poured Bar’s Leaks into the radiator to stop a slow coolant leak out of the intake manifold.
I drove full tanks at different speeds on cruise and averaged:
- ~13 MPG city
- 20.44 MPG at 55 highway (sorry truckers, thanks for not throwing your pee bottles on my windshield)
- 19.53 MPG at 60 highway
- 18.81 MPG at 65 highway
It’s been a hell of a truck, and now in Florida I have a garage + time, and will do some maintenance. Here is my list, I appreciate any suggestions (or requests):
driver side rear caliper/pads/hose (the wheel is a little warmer than the others after driving, and it just started to whistle though pads/rotors are only 13K miles) front rotors and pads, total brake fluid flush check if front hubs need replacement (I occasionally hear a noise when turning left at very low speeds) oil change w/ amazon synthetic + mobil 1 filter trans fluid flush w/ Dexron VI, new filter, and tighten valve body bolts (sometimes tranny thumps from a stop after highway driving, but the fluid is still pink enough) spark plugs and wires (just tested resistance, 7 AC Delco wires are perfect, at about 660 ohms but the 1 shorter Denso wire is at 505 ohms; double platinum AC Delco 41-962s have some gray and orange and could probably go back, but I’ll change just because I went through the trauma of removing them - BTW, three out of the eight plugs have oil in the threads, should I be happy?) fan clutch (not a lot of resistance, and my ac belt “jackhammers” when moving from idle - which according to some of the forums might be due to higher freon temps at idle due to a dying fan clutch) fuel filter clean and seal all grounds both downstream oz sensors (voltage is getting lazy)
I’m predicting that between the freed caliper, new plugs/wires, fuel filter, trans fluid and oz sensors I will see some mpg improvement over the next 10K miles, which will hopefully cover the Pacific Southwest, California and Pacific Canada. Thank you all for sharing you knowledge here, I look forward to putting it all into practice.
By Trevor Lucas
I own a 04 chevy silverado 1500. The brakes are spongy ( I've bleed them throughly, new everything except booster and master). My work trucks brakes are great 06 Sierra 2500 hd dual piston calipers all the way around same pads as the ones in my chevy. The question is can I upgrade to a dual piston the rear? They currently have the wimpy single piston. If an upgrade is possible do I need to upgrade the Master cylinder to accommodate the extra volume? If so can I just order the 2500 hd master cylinder?
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