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02-06-2021, 09:32 AM | #1 |
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Join Date: Aug 2017
Location: Euclid, Ohio
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Right Rear Drum Brake issue has everyone stumped
I have had three different shops work on by right rear brake issue. 1st shop was a mistake on my part. 2nd & 3rd shops both ASE certified and well established in the neighborhood. I have a 1982 SWB. It came with a 4.1 automatic and disc frt. & drum rear. Every part that i could get has been replaced TWICE. OE when available and the best A/market I could find for all the rest. Drums, Shoes, Hardware, Wheel Cylinders have been replaced except the backing plate & the rear axle seals. E-Brake completely removed. Tried at least four A/market drums none worked. All bottomed out on the backing plate causing a bind. Ended up turning the original (I think it's original) drum and running it. Now the wheel gets pretty hot when driving. Every brake part Frt/Rear has been replaced including the Master/Booster. All steel lines are original and have good flow for bleeding. Near as I tell this truck never had a proportioning valve. I can't work on my truck anymore due to an arm injury but both shops allowed me to observe the repairs and their honest attempt at fixing it. I have countless drum brake repairs myself and I'm the first guy to say this "shouldn't be that hard" but here I am. Thanks in advance
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02-06-2021, 10:14 AM | #2 |
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Re: Right Rear Drum Brake issue has everyone stumped
I assume you've replaced the brake hoses?
Every truck came out of the factory with a proportioning valve. It's mounted directly below the radiator. If that's been removed and replaced with a couple of tee fittings, that could possibly be causing this.
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02-07-2021, 07:31 AM | #3 |
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Re: Right Rear Drum Brake issue has everyone stumped
Thanks everyone I looked everywhere underneath and could not find a portioning valve or where one might have been. I will take another look to be sure. I was under the impression that not all squares had one. The original used drum does spin fine when the wheel is bolted on. I'm confident saying it's not the backing plate. The only non replaced part on the complete system is the original steel lines and of course the old rear drum. The reason for replacement in the first place was just normal upkeep and upgrades or so I thought. Other than fronts being about 60% worn out there was NO issues.
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02-07-2021, 11:00 AM | #4 | |
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Join Date: Jul 2000
Location: North Texas
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Re: Right Rear Drum Brake issue has everyone stumped
Quote:
But I'm confused. Didn't you say your problem is the brake drum rubbing the backing plate? If that's the case, it's a mechanical problem, not hydraulic. Please better explain your symptoms. Thanks.
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Mike 1969 C10 LWB -- owned for 35 years. 350/TH350, 3.08 posi, 1st Gen Vintage Air, AAW wiring harness, 5-lug conversion, 1985 spindles and brakes. 1982 C10 SWB -- sold 1981 C10 Silverado LWB -- sold, but wish I still had it! 1969 C10 (not the current one) that I bought in the early 1980s. Paid $1200; sold for $1500 a few years later. Just a hint at the appreciation that was coming. Retired as a factory automation products salesman. Worked part-time over the years for an engine builder and a classic car repair shop. Member here for 24 years! This is the very first car/truck Internet forum I joined. I still used a dial-up modem back then! Last edited by MikeB; 02-07-2021 at 02:48 PM. |
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02-07-2021, 05:07 PM | #5 |
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Re: Right Rear Drum Brake issue has everyone stumped
This. There is a mechanical issue causing a clearance problem from the sound of things. If this was my truck, I would remove the rear axle cover and inspect the cross pin, axle shaft, and C-clip for abnormal wear, if the drum has enough inward movement to contact the dust cover. Also, is the drum seating on the axle shaft flange completely, or does it contact the dust cover first?
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02-06-2021, 10:15 AM | #6 |
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Re: Right Rear Drum Brake issue has everyone stumped
If you had 4 different drums bottom out on the backing plate , that narrows it down..
Is the backing plate bent,?... how much end play does the axle have... is the bearing worn? .I'd pull the axle out and look at it..especially the c clip area... .if your thinking the brakes are dragging, did you replace the brakes lines? Rubber lines are notorious for interior breakdowns and acting like check valves...
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Mongo...aka Greg RIP Dad RIP Jesse 1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598 Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334 Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563 2023 Chevy Z71..daily driver |
02-06-2021, 01:49 PM | #7 |
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Re: Right Rear Drum Brake issue has everyone stumped
Prop valve on these trucks are down on the front x-member below the radiator. Bad valve would affect both sides. What engine is in this truck? If I remember correctly the diesel/big block trucks had wider brake shoes and drums. AND how were the brakes before you started all of this. Pics of the assy with the drums off.
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02-06-2021, 03:19 PM | #8 |
State of Confusion!
Join Date: Jul 2002
Location: Gulfport, MS USA
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Re: Right Rear Drum Brake issue has everyone stumped
Yep there are 2 sizes drums. I know 6 bangers uysed the narrower (2" I think). Not sure what ones had the wider wether iut was all V8 or just some options. AS mentioned, your proportioning valve is hidden to normal folks up on the from cross member near radiator.. I agree that maybe you might have a bent or messed up backing platye from the sounds of it, if they gave you the correct 6 cylinder drums.
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Bill 1970 Chevy Custom/10 LWB Fleetside 2010 Toyota Tacoma PreRunner SR5 Double Cab - DD Member of Louisiana Classic Truck Club (LCTC) Bill's Gallery Life isn't tied with a bow, but it's still a gift. Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God! |
02-06-2021, 03:48 PM | #9 | |
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Re: Right Rear Drum Brake issue has everyone stumped
Quote:
I'd measure the distance from axle flange (where the wheels mount) to a spot on the backing plate on left and right sides. And I'd probably remove the diff cover and take a look at the axle ends and C-clips as suggested above. There's something not right there. Bet I could find it in a couple hours, but charging brake parts won't fix it.
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Mike 1969 C10 LWB -- owned for 35 years. 350/TH350, 3.08 posi, 1st Gen Vintage Air, AAW wiring harness, 5-lug conversion, 1985 spindles and brakes. 1982 C10 SWB -- sold 1981 C10 Silverado LWB -- sold, but wish I still had it! 1969 C10 (not the current one) that I bought in the early 1980s. Paid $1200; sold for $1500 a few years later. Just a hint at the appreciation that was coming. Retired as a factory automation products salesman. Worked part-time over the years for an engine builder and a classic car repair shop. Member here for 24 years! This is the very first car/truck Internet forum I joined. I still used a dial-up modem back then! |
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02-06-2021, 08:57 PM | #10 |
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Location: Austin, Texas
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Re: Right Rear Drum Brake issue has everyone stumped
at this point, maybe do a disk brake conversion
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02-07-2021, 12:16 PM | #11 |
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Re: Right Rear Drum Brake issue has everyone stumped
Try one of the drums that dont work on the left side and see if it rubs there...or swap drums side2side and see what happens
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Mongo...aka Greg RIP Dad RIP Jesse 1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598 Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334 Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563 2023 Chevy Z71..daily driver Last edited by mongocanfly; 02-07-2021 at 12:21 PM. |
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