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73-87 Chevy _ GMC Trucks => Brakes, Frame, Steering & Suspension => Brakes and Braking Systems => Topic started by: TheWaterboy on June 26, 2016, 12:47:25 pm
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Hey Everybody,
I am new here, and i have a brake issue that I can just not figure out. I am restoring a 1986 c10, My problem is with the rear brakes.
What it is doing- acts like the driver side wants to drag/get hot/ lock up when I get on the brakes even a little hard when its dry out and almost instantly when its wet out. Also the brake pedal seems to be inconsistent sometimes it is high and sometimes it is low.
What I have Done- NEW ( wheel cylinders, shoes, drums, hardware,E-Brake cable/**all three, Brake hoses** all three, star adjusters on both sides, cleaned and lubed backing plates, new calipers, pads, rotors, all quality AC Delco parts. I have adjusted them and had them adjusted. Also bled the entire system and filled with new fluid.
Still no fix, I am at a loss.....Please any help would be greatly appreciated!!
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It looks like you are doing a high quality repair, replacing everything. Good for you. Hopefully we can get it straightened out. There are some really sharp guys on here, until then maybe I can get you heading the right direction.
The first thing that concerns me is "cleaned and lubed the backing plate". With what? No grease or oil should in there, except antiseize on the adjusters. I guess a dry graphite spray would be OK, but I've never lubed the backing plate. Grease or oil on the shoes could cause what you're describing. Throw the shoes away and get new ones if the linings are contaminated. Clean the drums and backing plates with brake cleaner.
Next the adjusters are different on each side. One side has left handed threads. Some pictures of how everything is assembled would be helpful.
You may still have air in the lines. With all 4 corners new and the rear brakes adjusted, you should have a firm pedal. How are you bleeding the brakes? I don't want to insult you, but are the bleeder screws on top? I've seen calipers installed upside down on the wrong sides. Just trying to eliminate problems.
If everything else is good, the master cylinder could be bad. Were the brakes working good before? Or is this a truck that's been sitting a long time?
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are you sure its the rear brakes and not the front?
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A couple pictures of our rear brakes in Members rides. Find "Brooke's 87 V10" look for reply #48 on page 4. Sorry don't have the pics on my new laptop yet, so I couldn't just post the pictures.
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Hey Captain,
With the backing plates I just cleaned with brake cleaner and a wire brush then put a small amount of Anti seize on the ware locations(I could not attach the photo I have but there are 6 oval nubs the metal part of the shoe rubs against) All the bleeders are on the top, I am bleeding them the old fashion way with a friend in the truck, pump it up 6-8 times and crack open the bleeder with a clear tube attached leading to a catch canister. Keeping the pedal depressed until the bleeder is tightened. Then repeat.
The ruck was siting a bit a little back story this was my first car, I sold it in 2010 to help my
Mother pay for hospital bills acquired do to a cancer battle that my Dad was fighting. Unfortunately a year latter he lost that fight. I never thought i would see this truck again, it was purchased by my grandfather in 87. My Dad taught me how to work on cars through this truck, we did a little of everything. This truck was a Texas truck with 60xxx miles on it when I got it...beautiful, like new. Around June of 15' I decided I wanted another square body, the search began..... Three months later not only did I find a square body, I found my truck in Indiana. When I found it it had 91xxx miles and the power train including rear gear had been swapped, all the trim removed >:(, and some small damage on the bed sides >:(. I was able to buy it back and that is where the restoration began, Now I have the power train lined out with a new GM Long Block and rebuilt TH350. I am not sure how much it sat while out of my possession the mileage would indicate that i could have sat a while. When I sold it had around 78xxx so 13 thousand miles in 5 years is not much but i only put 18 thousand on it when i had it
Irish Alley,
I am sure it is the back I have done a few things to check this. First had a friend watch as I hit the brakes and confirmed only the rear Driver side was locking up. then had them drive around in a parking lot and i watched and listened for the squeal( they can be very deceptive) but i also took a ride in the bed to try to double check. All signs point to the driver rear, including the excessive dust that accumulates in between tear downs. Oh and that wheel is getting hot after any real length of driving.
P.S.
Sorry for the long reply
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Hey Captain,
I am not to great at navigating this forum yet, how would i go about finding that?
thank you
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Here is the thread:
http://forum.73-87chevytrucks.com/smforum/index.php?topic=32209.45 (http://forum.73-87chevytrucks.com/smforum/index.php?topic=32209.45)
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thank you amplifiedsilence, mine is a little different it is 5 lug but otherwise looks the same,I still can't upload pictures or i would put one of mine up :(
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I was worried grease was dripping into the drum. The anti seize should be OK. Sounds like it is adjusting to tight. Try removing the self adjuster arm. Then test drive.
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Okay I will try that, I picked up a new Ac Delco MC too. I am going to change that out and see where it gets me. I was looking at them last night and one thing i did notice that seemed odd was that the adjuster arm did not "ratchet" "Click" when turning the star wheel. I am not sure if it is supposed to or not. It was not making very firm contact, I have an old haynes manual and it said I should have to lift the arm to adjust and i do not at all.
I would think that would cause it to not adjust, as apposed to adjust to tight?? AHHHH who would think the Motor swap would take less time and cause less headache LOL
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Okay so an update on this headache, I set the initial brake adjustment way out and took it for a drive about 2 miles in and the Driver rear started to drag. I made sure that i never went in reverse ...I thought they only adjusted when braking in reverse??? I am so frustrated at this point I and tired of throwing money at it. Again once it starts to squeal, the driver side starts to lock up very easily even on hot dry pavement and when that starts you can walk next to the wheel and feel/smell the heat and the center cap/ rim is hot to the touch.
HELP!!!
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#1 post pics of both sides with the drum off. Indicate in your pics L and R and a pic of the inside of each drum. (have you swapped the drum left to right to see if the noise problem goes to the other side?
#2 make sure the parking brake cables are loose and not pulling the shoes away from the anchor pin.
#3 double check all of your hardware is on correctly and the that the primary and secondary shoe are in their respective locations
#4 inspect the drums for improper machining and wear.
The shoes should be fully seated on the anchor pin and must be adjusted to minimal contact with the drum. Once you have them properly adjusted and working correctly, then you can adjust your parking brake cable slack. Do not over adjust it
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This is the Driver side the one locking up and getting hot, I think the squeal is a result of that. I had just removed the one return spring but this is what everything else looks like. As far as the E-Brake I have it adjusted very loose, I ill get about 2-3 good stops between the rear being out of adjustment and me having long pedal travel to over tight on the drivers side.
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Looking at the picture, the primary shoe (shortest, closest to front) looks too long to me.
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The brake material stops about at the arrow if my memory serves me
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that's interesting I have double checked the part number, that is the part i have. The other side is the same and it has not given me any issues. Here is the other side
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Also to note I did realize the stud( in the upper left ) for the parking brake arm was out of place the clip had come off. That was corrected.
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When all the springs are put on and it is adjusted, do the top part of the shoes meet firmly against the top stud? Red arrow
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Yes is was only like that because i had the one spring off.
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I really appreciate all you help, I just put a new motor in and its killing me that i can't really get out and enjoy it >:(
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If the parking brake cable hasn't released 100% or the spring on the cable is weak sometimes you have to grind the slot deeper (blue arrow)
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It does seem to be releasing, I had it on a lift and put it in gear (drive and reverse) I applied the brakes and the parking brake several times it released every time. I did that for about 5 miniutes then let it down and took it for that 5 mile trip and half way though it started acting up.
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It does seem to be releasing, I had it on a lift and put it in gear (drive and reverse) I applied the brakes and the parking brake several times it released every time. I did that for about 5 miniutes then let it down and took it for that 5 mile trip and half way though it started acting up.
Try taking a large screw driver and pry the parking brake lever under the adjuster to the rear of the truck. Mine releases but not all the way. If that doesn't do it I am out of suggestions
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One more possibility is did you take brake clean to the new drums to clean the rust preventative off?
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I did clean them off but I have also been dealing with this issue well basically sense i bought the truck back in September of last year. All the brake work I have done has been chasing the same problem so I don't think it is a bad part.
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I am at a loss shy of machining one pass of the drums and scuffing up or replacing the rear shoes again to see if maybe the composition of the shoes may be of fault. Does your state have inspections of trucks? I used to have to run mine and it would stop on 4 pads to check the ratio of front to rear braking and would indicate if further inspection of the brakes were needed...
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Can you get a picture of the other side?
I believe zeig85 is correct. You have both trailing shoes on this side.
You probably have both leading shoes on the other side.
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Can you get a picture of the other side?
I believe zeig85 is correct. You have both trailing shoes on this side.
You probably have both leading shoes on the other side.
Hey, Reply #16 has a picture of the other side , both have the short shoe in the front though.
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Is the adjuster actuator hanging up on a burr on the shoe or the E-Brake arm?
Have you tried swapping drums LH to RH?
Have you tried swapping linings from LH to RH?
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The brake material stops about at the arrow if my memory serves me
besides the one hanging spring, it looks just like my brakes(untested yet, but I followed the old set up and they worked fine before)
both sets of brakes shoes(old and new) the pad went right to the lower dimple.
I would make sure you have the washer that goes in behind the adjuster arm, if it is missing, you will have a little slop, and that could be causing it to adjust in forward motion.
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Make sure you have the correct adjusters on each respective side. Double check the drums, try swapping the drums L to R and see what happens.
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Hey Everybody,
Thank you to everybody that has responded. I have now replaced the Master cylinder, I do think the seels were going out on it the pedal feels a lot better. However the original issue remains. I also pulled apart both rear brakes and checked for any mistakes, I did find one on the side that has not been giving me issues. The parking brake strut was incorrectly installed. I also cleaned the backing plate to bare metal on the "wear bumps" and applied a very small amount of anti seize to them. There are some ridges in a couple, I will need a grinder to repair. What i still need to try is swapping drums and shoes LH to RH ( I had not does this because I had replaced the driver side drum and the shoes once already and made no change ) and then replacing hard lines?? and trying new shoes?? It has to be something simple ....... I am on week 4 of trying to resolve this
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If everything is correct as you say it is simply swap the drums left to right. If the drum is improperly machined there's your problem. You aren't over adjusting them are you?
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If everything is correct as you say it is simply swap the drums left to right. If the drum is improperly machined there's your problem. You aren't over adjusting them are you?
I am adjusting until they drag a little then backing off 4 teeth. However I also tried having them backed off enough where they were not contacting at all and the driver still slowly became over tightened again. Within my 5 mile test loop
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again, do you have the correct adjuster screws on their respective sides? They are not the same L and R, even though it's been mentioned a few times I haven't seen you acknowledged this.
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again, do you have the correct adjuster screws on their respective sides? They are not the same L and R, even though it's been mentioned a few times I haven't seen you acknowledged this.
Hey sorry I thought I did . The driver side is regular thread and the passenger side is reverse thread. I do believe that is the correct positioning.
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I wonder if the top anchor pin is worn, this will allow the shoe to rock forward with braking, and cause the adjuster lever to adjust the shoes out. Rather then the springs and rods working the adjuster lever.
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Okay so an update on this issue I disassembled the rear brakes again....swapped the shoes and ground down the groves I found in the backing plate on the wear bumps and put a small about of anti seize on them. So far it has dramatically reduced the issue but not completely solved it there is a consistent sound under braking like a rhythmic scrape and an occasional squeal I took it for a ~ 30 mile trip stopping every so often to check for excessive heat. The driver side rear is still the warmest by quite a bit but no where near as hot as it was getting before. So I think the drum was over heated and will need to be turned or replaced and possibly get higher quality brake shoes? With this change in symptoms any additional thoughts??
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Brakes are supposed to get hot. They work on the principal of friction and heat. If you jack it up with the wheels on and they spin freely, aren't locking up or grabbing, pedal feels good, then your only complaint should really be your noises.
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Yes I am aware of how brakes work and that they typically produce heat... I am not referring to a normal level of heat. Part of the original symptom with the dragging shoes obviously was the increase in heat on that corner. I have an Infrared thermometer and checked the drums on both sides in an attempt to quantify " being hot" The passenger side was what I would consider a normal temperature at around 125-140 while the passenger side got to around 295-320 in the same trip under regular driving not exceeding 50mph on a 10-15 mile trip. Now the driver side is at 180-200 and the passenger side still at 125-140 after a 45 mile trip including highway speeds ending in the same 10 mile loop from the previous test. So I feel like I have reduced the problem. I know the drum on that side was way over temp but in my experience that would not cause that system to keep getting hot, the sound could be caused by the drum if it is warped.. maybe?? Usually it would cause a pulse from what I have seen.
Brakes are supposed to get hot. They work on the principal of friction and heat. If you jack it up with the wheels on and they spin freely, aren't locking up or grabbing, pedal feels good, then your only complaint should really be your noises.
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There are many reasons the drum could be the issue aside from out of round. Simply swapping the drums would reveal if it were the issue.
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Problem Solved!! So as i said in a previous post, i ground out the grooves in the backing plate. I thought this had pretty much resolved the brake sticking problem. I was left with a little bit of extra noise and heat coming from the same driver rear. I swapped the drums and the sound went with the drum, I looked at getting both turned but the cost was 2/3 what a new AC drum cost from Rock Auto so i went that route and also replaced the shoes with AC shoes as the ones that were on there where cheepos. It is working great now no sound or excess heat, So thanks for all the help! Glad that's over with now on to servicing the Rear diff and then a little body work.
p.s Another issue i had was I thought i got all the transmission fluid out of the converter when i had it out and filled it to spec, that was about 1.5 quarts to many.... But figured out a easy way to get that extra fluid out. My truck has a Trans cooler built into the Radiator I just detached the bottom line put a clear rubber hose on the end. Then i disconnected the power to the Coil and cranked the engine with the hose leading to an empty transmission fluid container. It pushes out a quart pretty quick so heads up if you are not careful you will drain to much. I did by about 1/2qt but putting it back in is the easy part.