just a number
Active Member
that one I don't happen to know. proper tool is the flare nut wrech but there not alot of room in there. you rounded of the line that's there?
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how to PM rear brakes on a '99 C3500?
- Thread starter coachjpg
- Start date
No, I haven't attempted these brake line fittings yet. Weeks ago I was working on corroded fuel line fittings, and they were hopelessly fused together. I rounded them off trying to get them apart, then I replaced the fuel line with fuel hose.
I'll get a set of flare wrenches. I'll need them anyway when I replace the brake lines.
Thanks!
-jpt
I'll get a set of flare wrenches. I'll need them anyway when I replace the brake lines.
Thanks!
-jpt
just a number
Active Member
If you do end up replacing the rear lines, take one to the cylinders to find the line size. make sure you plug off the line where it connects to the rest of the system. one brake fluid will absorb water and second the less yoiu get it there the less you gotta bleed out.
btfarm
America First!
Use a 6 pt deepwell socket to get the bleeder fitting out. Heat it up first if you want. I have before with no ill effects. I recommend just doing all new wheel cyls anyhow. The brake line fitting is big enough that you probably won't round it off with a 6 pt style flarenut wrench.
I got the brake fitting out without ruining anything. What do you folks use to plug the brake lines while you're working? I wrapped it with electrical tape, to keep it clean, but the brake fluid seems to dissolve the adhesive on the tape, so I'm not optimistic that this is a good approach.
First I wire-brushed the area to get rid of as much corrosion as possible. I got a set of craftsman flare wrenches, on the theory that cheap tools might have contributed to my previous failures. I sprayed the fittings with PB penetrating oil several times over the course of a day.
I never found a wrench that fit properly. 9/16 was the smallest size I could get on the fitting, but it felt looser than I'd like. I also tried metric sizes of course, but the smallest metric I could get on the fitting was even looser than the 9/16. Perhaps enough of the fitting corroded away to make it smaller. Perhaps the corrosion I couldn't remove caused the fitting to swell.
The space is very tight. I could only get about 60 degrees of rotation, and re-positioning the wrench involved awkward contortions every time. It took a long time to get the fitting off, so I had time to think. At one point, I decided it would be faster to unbolt the plate to which the shoes attach, slide it out a few inches along the hub, and give myself space to work. I tried this, but I couldn't get the plate loose. I removed the bolts, and banged on it a bit, but it wouldn't budge. Is there a trick to this?
The bolts that hold the cylinder in place also don't seem to be any standard size. Again, I tried metric and standard sockets. Again, I suspect corrosion either swelled or reduced the bolt sizes. The location of the bolts make it impossible to get a regular socket on them, and there isn't enough space for an extension. I could probably use a deep socket, or an adapter as a short extension, if I could figure out the size to use. Again, I tried to remove the plate so I could get better access, and again it wouldn't budge.
If I could get the plate off, I'd also clean up all the rust and corrosion I can reach while it's off. Otherwise, I'll figure out the best socket I can get onto these bolts, and work out a way to function in the cramped space.
Thanks again for all your support.
-jpg
First I wire-brushed the area to get rid of as much corrosion as possible. I got a set of craftsman flare wrenches, on the theory that cheap tools might have contributed to my previous failures. I sprayed the fittings with PB penetrating oil several times over the course of a day.
I never found a wrench that fit properly. 9/16 was the smallest size I could get on the fitting, but it felt looser than I'd like. I also tried metric sizes of course, but the smallest metric I could get on the fitting was even looser than the 9/16. Perhaps enough of the fitting corroded away to make it smaller. Perhaps the corrosion I couldn't remove caused the fitting to swell.
The space is very tight. I could only get about 60 degrees of rotation, and re-positioning the wrench involved awkward contortions every time. It took a long time to get the fitting off, so I had time to think. At one point, I decided it would be faster to unbolt the plate to which the shoes attach, slide it out a few inches along the hub, and give myself space to work. I tried this, but I couldn't get the plate loose. I removed the bolts, and banged on it a bit, but it wouldn't budge. Is there a trick to this?
The bolts that hold the cylinder in place also don't seem to be any standard size. Again, I tried metric and standard sockets. Again, I suspect corrosion either swelled or reduced the bolt sizes. The location of the bolts make it impossible to get a regular socket on them, and there isn't enough space for an extension. I could probably use a deep socket, or an adapter as a short extension, if I could figure out the size to use. Again, I tried to remove the plate so I could get better access, and again it wouldn't budge.
If I could get the plate off, I'd also clean up all the rust and corrosion I can reach while it's off. Otherwise, I'll figure out the best socket I can get onto these bolts, and work out a way to function in the cramped space.
Thanks again for all your support.
-jpg
just a number
Active Member
the 4 bolts hold the backing plate to the axle are hard ones to get out. IIRC it took my 18" breaker bar to loosen mine when I changed the rear axle. you can heat/soak the with no worriers. there nothing there to hurt.
To keep things clean and prevent leaks, I found either a plastic bag tied over the end, or a short piece of fuel line with a bolt jammed in the other end works too.
To keep things clean and prevent leaks, I found either a plastic bag tied over the end, or a short piece of fuel line with a bolt jammed in the other end works too.
just a number
Active Member
rust is a good friend in there. try hitting the thinker mounting plate. the vibration might break it loose. the plate is just slid over, not pressed on or anything.
I wire brushed off the corrosion where the parts meet, sprayed it with PB, put a 2X4 against it and pounded away with a small sledge. No movement. So I tried hitting the steel directly with the sledge, and rust rained out of the joint. I started with gentle blows, moving from corner to corner and slowly increasing the force of the blows until it came loose.
The cylinder is held in place with 1/2" bolts, I believe. I wire brushed them, and then used the sledge to get a 1/2" impact socket onto them. It took some effort, but they came off. I had to use the sledge to get the old cylinder free also. I put a punch at the bottom of the 1/2" bolt holes, and repeated my gently increasing pounding approach.
When I cleared the rust from the hole left by the cylinder, I was surprised to see that the bolt holes met the larger opening in the plate. Kind of like ears on Micky Mouse. The bolt holes originally appeared to be separate holes, but they were separated only by rust. I'll put up a picture later. I'm curious whether this is as designed, or if I have to replace the plate. I was planning to treat the rust and re-install it...
Thanks again for all the advice.
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The cylinder is held in place with 1/2" bolts, I believe. I wire brushed them, and then used the sledge to get a 1/2" impact socket onto them. It took some effort, but they came off. I had to use the sledge to get the old cylinder free also. I put a punch at the bottom of the 1/2" bolt holes, and repeated my gently increasing pounding approach.
When I cleared the rust from the hole left by the cylinder, I was surprised to see that the bolt holes met the larger opening in the plate. Kind of like ears on Micky Mouse. The bolt holes originally appeared to be separate holes, but they were separated only by rust. I'll put up a picture later. I'm curious whether this is as designed, or if I have to replace the plate. I was planning to treat the rust and re-install it...
Thanks again for all the advice.
-jpg
btfarm
America First!
IIRC the cyl bolt holes are open to the center hole originally. Yeah it looks wrong...
A golf tee stuffed in the brake line works if you hold it in place with a plastic bag or a balloon taped to the line farther up.
As an aside... I've worked on some rusty shit but you're running neck and neck with my worst ever...
A golf tee stuffed in the brake line works if you hold it in place with a plastic bag or a balloon taped to the line farther up.
As an aside... I've worked on some rusty shit but you're running neck and neck with my worst ever...
Golf tee -- sounds good. Thanks.
The drive train on this truck is well maintained. The tranny is new. The body has typical rust. The utility bed is close to ideal for my purposes. The undercarriage has rust issues, as you've seen.
I sometimes wonder if it's worth fixing, or if it's a money pit. I think it's a good truck for me to learn on. I hope.
The mechanic quoted me $1200 to re-do the back brakes. So far I've spent about $100 on parts & materials, and $200 on tools (flare wrenches, bigger torque wrench and breaker bar, impact sockets, grease gun). While I'm in there, I'm treating rust wherever I find it, which the mechanic certainly would not do.
Probably the biggest plus for me is intangible. My father was a mechanic, and I remember as a kid pulling the drum brake adjuster tool out of his tool box and asking what it was. He explained, and told me some stories about it. Now I'll get to use that tool for the first time. He's been gone 30 years, but when I use his tools it brings back lots of memories.
So yeah, the truck is rusty underneath. But I'm learning how to fix it, I'm enjoying the process, and I don't have to make loan payments on it. I'm hoping I'll at least break even in the end. So far, it's looking good.
Thanks again for all your support,
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btfarm
America First!
Great attitude!:agreed:
I'm still using a few of my Dad's tools and he's been gone 40+ years so I know what you're thinkin':thumbsup:
I'm still using a few of my Dad's tools and he's been gone 40+ years so I know what you're thinkin':thumbsup:
OK. Here are the pictures I promised. The axle without the Backing Plate:
The backing plate.
The "Mickey Mouse" shaped hole for the wheel cylinder. The ears are the bolt holes.
One of the wheel cylinder bolts. To get a 1/2" socket on these, I had to wire-brush off the loose rust, and then use a hammer to get a 1/2" impact socket on them. To do that I had to first remove the backing plate, to gain room to work. I also soaked them half a dozen times in PB over the course of a couple of days, but I'm not sure that helped at all. I need to get replacements for these. Then I think I have all the parts I need for reassembly, once I clean up the rust.
AutoZone had all the parts I needed except the little plungers that stick out the sides of the wheel cylinder. They expect me to re-use my old ones. NAPA says bring in an old one and they'll try to match it. I'll see how they clean up. I'm starting to see the benefit of owning a parts washer...
The backing plate.
The "Mickey Mouse" shaped hole for the wheel cylinder. The ears are the bolt holes.
One of the wheel cylinder bolts. To get a 1/2" socket on these, I had to wire-brush off the loose rust, and then use a hammer to get a 1/2" impact socket on them. To do that I had to first remove the backing plate, to gain room to work. I also soaked them half a dozen times in PB over the course of a couple of days, but I'm not sure that helped at all. I need to get replacements for these. Then I think I have all the parts I need for reassembly, once I clean up the rust.
AutoZone had all the parts I needed except the little plungers that stick out the sides of the wheel cylinder. They expect me to re-use my old ones. NAPA says bring in an old one and they'll try to match it. I'll see how they clean up. I'm starting to see the benefit of owning a parts washer...
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just a number
Active Member
the plungers should be part of the new cylinder. the reason you don't reuse one is because you can get a small ridge/grove from the wear. if the piston get out of it's little wear spot you may end up with a leak. not that'll it'll happen every time but it's a easy CYA.
I'm not sure of the proper part names, and I'm afraid I've miscommunicated.
My new cylinder came with a bleed screw, a spring, 2 plungers, and 2 dust boots. There is a rod that sticks through the center of the dust boot, that sits between the plunger and the shoe. That rod is the part I'm expected to re-use.
What is the proper name for that rod?
My new cylinder came with a bleed screw, a spring, 2 plungers, and 2 dust boots. There is a rod that sticks through the center of the dust boot, that sits between the plunger and the shoe. That rod is the part I'm expected to re-use.
What is the proper name for that rod?
btfarm
America First!
Actuator rod IIRC and those can usually be polished up in the drill press with some emery. Plenty of interference with the boot so if they get a bit undersize on cleanup it won't matter. Use white lube on them, and every other contact point for that matter.
just a number
Active Member
can't say I've ever heard of doing it the way. good point on the lube.
I just went through my newly-acquired service manual, and these "actuator rods" do not appear in any of the exploded diagrams of the brakes or the wheel cylinder. The index mentions a number of actuators related to power door locks etc, but not related to brakes.
The manual uses the term "pistons" for the items inside the cylinder separated by the spring.
Even with the full 4-volume Service Manual for my specific vehicle, I still need you guys to fill in the gaps.
Thanks again,
-jpg
The manual uses the term "pistons" for the items inside the cylinder separated by the spring.
Even with the full 4-volume Service Manual for my specific vehicle, I still need you guys to fill in the gaps.
Thanks again,
-jpg
Here is the next chapter in the continuing saga.
I treated the rust with wire brush, naval jelly, rust reformer, and rustoleum. When I came into the house after wire-brushing the rust, my wife told me I looked 10 years younger. The rust dust covered the gray in my hair...
I reassembled the brakes, using new parts. I installed the wheel cylinder while the backing plate was off. In order to have enough room to work, I connected the brake line before installing the backing plate bolts. The backing plate comes on and off simply enough. I'll never again try working behind it without first unbolting it and sliding it a few inches down the axle. There's simply not enough room back there for someone with large hands to work.
I have some questions, and I'm having trouble with the parking brake cable. First, some pictures of what I did:
Here is the backing plate reinstalled with the parking brake cable and the new wheel cylinder. I couldn't buy wheel cylinder bolts that would match the old ones, so I bought longer ones and cut them down to length. I used stainless bolts this time, in hopes of avoiding the corrosion problems evident in the old bolts.
Here we have the parking brake lever, its clip, brake shoes, adjusting screw, and the first spring in place.
The parking brake transfer bar and its spring fell out several times as I struggled to get all the parts in place.
The self-adjusting mechanism and the nails and springs that hold the shoes to the backing plate:
The rods that connect the shoes to the cylinder, and the remaining springs:
I'm pretty sure I have all the parts installed correctly, but I have questions. First of all, the rearmost shoe sits much closer to the backing plate than the foremost shoe. Is this normal? I wonder if I have the springs reversed. The green spring I installed on the back nail is longer than the yellow one I installed on the front nail. The green one has a bit of a taper that seems designed to fit into the cup formed by the self-adjusting arm's pivot...
Left picture is front of brake.
The parking brake bar touches the backing plate in the rear, but it's about 1/4" away from the backing plate in the front. Is this normal?
And finally, my parking brake issue: Remember, my problems started when I paid $300 to have a new parking brake cable installed, so the truck would pass inspection. I had to go back twice because "GM sent the wrong cable". I wonder if they just installed the wrong cable, causing my problems. Now, I can't get the cable back together. Before disassembling my brake, I disconnected the parking brake cable below the rear passenger door, as it says in the manual. To re-install it, I had my middle-linebacker son push the brake lever forward while I pulled the cable. I could not get enough slack to reconnect the cable. Yes, the foot-pedal is disengaged and all the way up.
If you guys can talk me through fixing the parking brake, that would be great. Or maybe I'll tie up the loose ends of the parking brake cable and take it back to the guy who "fixed" it before. In that case, I need to reinstall the drums & wheels, & bleed the brakes. I also need to clean and lube the bearing, install the new seal, & top off the diff lube. Have I missed any steps?
Do you folks see any problems/issues in the assembly so far?
Thanks again,
-jpg
I treated the rust with wire brush, naval jelly, rust reformer, and rustoleum. When I came into the house after wire-brushing the rust, my wife told me I looked 10 years younger. The rust dust covered the gray in my hair...
I reassembled the brakes, using new parts. I installed the wheel cylinder while the backing plate was off. In order to have enough room to work, I connected the brake line before installing the backing plate bolts. The backing plate comes on and off simply enough. I'll never again try working behind it without first unbolting it and sliding it a few inches down the axle. There's simply not enough room back there for someone with large hands to work.
I have some questions, and I'm having trouble with the parking brake cable. First, some pictures of what I did:
Here is the backing plate reinstalled with the parking brake cable and the new wheel cylinder. I couldn't buy wheel cylinder bolts that would match the old ones, so I bought longer ones and cut them down to length. I used stainless bolts this time, in hopes of avoiding the corrosion problems evident in the old bolts.
Here we have the parking brake lever, its clip, brake shoes, adjusting screw, and the first spring in place.
The parking brake transfer bar and its spring fell out several times as I struggled to get all the parts in place.
The self-adjusting mechanism and the nails and springs that hold the shoes to the backing plate:
The rods that connect the shoes to the cylinder, and the remaining springs:
I'm pretty sure I have all the parts installed correctly, but I have questions. First of all, the rearmost shoe sits much closer to the backing plate than the foremost shoe. Is this normal? I wonder if I have the springs reversed. The green spring I installed on the back nail is longer than the yellow one I installed on the front nail. The green one has a bit of a taper that seems designed to fit into the cup formed by the self-adjusting arm's pivot...
Left picture is front of brake.
The parking brake bar touches the backing plate in the rear, but it's about 1/4" away from the backing plate in the front. Is this normal?
And finally, my parking brake issue: Remember, my problems started when I paid $300 to have a new parking brake cable installed, so the truck would pass inspection. I had to go back twice because "GM sent the wrong cable". I wonder if they just installed the wrong cable, causing my problems. Now, I can't get the cable back together. Before disassembling my brake, I disconnected the parking brake cable below the rear passenger door, as it says in the manual. To re-install it, I had my middle-linebacker son push the brake lever forward while I pulled the cable. I could not get enough slack to reconnect the cable. Yes, the foot-pedal is disengaged and all the way up.
If you guys can talk me through fixing the parking brake, that would be great. Or maybe I'll tie up the loose ends of the parking brake cable and take it back to the guy who "fixed" it before. In that case, I need to reinstall the drums & wheels, & bleed the brakes. I also need to clean and lube the bearing, install the new seal, & top off the diff lube. Have I missed any steps?
Do you folks see any problems/issues in the assembly so far?
Thanks again,
-jpg
ak diesel driver
6.5 driver
I would avoid the use of the SS bolts as they are quite a bit softer than the originals. Braking can produce alot of torque. Also it seems to me that I have always had to connect the parking brake cable to the arm before assembly.