Rear caliper rebuild, looking for the Holy Grail.

[Texsardo]

I have read many threads on brakes, watched every youtube, looked at many books.
Problem, caliper rebuild going fine until time to replace the handbrake arm and the slotted shaft that fits into the back of the caliper. I used a large "G" clamp with the fixed end cut down to fit over the end of the piston rod. You know, the part that the key wedge fits in to allow the slotted arm to push down on the piston.
Well, the clamp worked perfectly for removing the arm by compressing the piston springs allowing the arm and slotted shaft with wedge to fall out.
Now I have tried for days to get the clamp to compress the rod into the caliper. The adjustable foot of clamp against piston and other end over the piston rod at back. Every time, it slips off the rod or turns the grooved rod head so that the brake arm and wedge would not line up, so the brake rod would not go back in.
1. Any suggestions?
2. Is the piston slotted end be able to turn so freely. I can turn it with finger and it is fully seated in piston. The piston is in the cylinder with only the second smaller slotted part sticking out about 3/8 of an inch past the piston opening in the caliper.
Texsardo

[Funcar]

I have not tried to rebuild the rear calibers. I do know that I had trouble compressing the piston. My problem was apply enough pressure and turning it in at the same time. I borrowed a caliber tool set from my mechanic and then it was easy to accomplish this task. I hope this helps you. I did post a picture of the tool kit under my first brake job.

[mscafide]

It's been a while but I recall the piston screws back in.

Mike

[Texsardo]

Sorry, I mean the rod at back of caliper with that goes into piston. I am trying to get this rod compressed enough to slip the hand brake with the key into this rod. The springs, ()()() this configuration is a heck of a strong pressure. The hand brake shaft is slotted and lines up with notch on this rod with the key slotted between so when hand brake is applied it pushes down on rod, which inturn pushes the caliper iston against the brake pad.
I might try to find a machine shop that has equipment for valve spring compression. They may have something that will work. Otherwise I don't see how anyone can DIY a rear caliper rebuild. And with the responses here, neither have most people on this forum.

[DanD]

Get a different clamp, or get a vice. I compress the shaft, then I reach inside the caliper and grab it with a small vice grip, so that I can take the clamp off. A vice and a couple of blocks of wood or whatever make short work of it.

I'm not saying that this is the best way, but it works. I haven't found any other way that works for me

[DanD]

Oh yeah. When you go to screw the piston back in, put some sil-glide brake assembly grease on it. It will screw right back in, and it will leave a little film of grease between the piston and the caliper bore outside of the seal, where water can get in and cause things to corrode and bind. Do this, and you may never have to rebuild your calipers again.

Brake assembly grease does not react with rubber, BTW. I also smear it on the outer seals, and it keeps them from drying out and cracking in a couple of years, as they are wont to do. It keeps them soft and pliable.

[azruss]

The bellevue washers are difficult to compress. I built the following tool to do the job.

[Texsardo]

Showed the photo of the cut down "socket" to my local machine shop. They made one like it, compressed springs and re-installed my hand brake assembly for $25.00 Thanks for the great tip. I have it all back together again and it brakes better than before. Hand brake is 200% improvement. It still is a bit soft. I will start looking for new threads on other work to firm up the pedal pressure some. But next week, I get to take front rebuilt calipers off with rotors and install new inner and outer wheel bearings.
Here hopefully are some photos of before and after brake job. First is old:


and here it is caliper after cleaning and rebuilding




New set up with new rotor, rebuilt caliper and I also had axle bearing and keepers replaced.

Thanks to all and if you know some tips on further firming up my brakes let me know. BTW, I had rear axle up on jack stands under the axle and the the rear regulator disconnected (left it disconnected until replaced) befire bleeding brakes. I also replaced bleeders with A/Ricombi speed bleeders . Using this method, I bled the brakes RR, LR, RF then LF twice. May bleed them again when I start work on front axles.
Texsardo

[micbrody]

I had same problems; but this thread helped a lot. I have everything back together. One thing worries me: i used brake fluid (Lucas synthetic dot 3) to lubricate seal and piston. After screwing around with assembly ( installing, removing piston multiple times), I noticed that the brake fluid seems to have dissolved a little of something ....either seal and/or dust cover, because the small amount of brake fluid used has a blackish tint. In addition, when I actuate emergency brake arm (on the workbench with caliper only filled with air, I can see tiny , dark gummy bubbles coming out between cylinder and bore. It's a very small amount ; hoping that brake
Fluid would seal this. One thought is during one of the attempts to install piston, the dust seal was trapped and dragged between bore and cylinder . Maybe just remanent rubber from that???

[DaveMarcotte]

Sorry, I mean the rod at back of caliper with that goes into piston. I am trying to get this rod compressed enough to slip the hand brake with the key into this rod. The springs, ()()() this configuration is a heck of a strong pressure. The hand brake shaft is slotted and lines up with notch on this rod with the key slotted between so when hand brake is applied it pushes down on rod, which inturn pushes the caliper iston against the brake pad.
I might try to find a machine shop that has equipment for valve spring compression. They may have something that will work. Otherwise I don't see how anyone can DIY a rear caliper rebuild. And with the responses here, neither have most people on this forum.

Mine had a total of 5 washers each. No problem other than having to do it twice as the first time i had the rod in the wrong configuration.

[same0027]

I just wanted to say for anyone else finding this post, I had the same experience as the OP. I spent days trying to get the clamp to compress the rod while simultaneously getting the shim in place. Placing the caliper in a vice while I tried to do this made all the difference. It is very tricky to get the g-clamp just on the lip of the rod. I also placed my large file across the face of the caliper which gave a better place for the clamp to rest against without interfering with the rod movement.

[grrrdot]

The bellevue washers are difficult to compress. I built the following tool to do the job.

Hi,
Raising this thread from the dead!
Looks like this Image is no more, anyone have a copy?
-G

[18Fiatsandcounting]

Sorry, I don't have a copy of the image, but I've been fairly successful at this task by clamping the caliper in a vise (taking care not to scratch the surfaces), then using a large channel lock pliers to compress across the piston opening and the longer protruding tip of the plunger. If you coat the wedge with grease to hold it into place on the plunger, and get the actuator arm ready to push in, compressing the springs with the pliers seems to work. At least for me, although it takes a few tries to get the hang of it. I suspect having just the right size and jaw angle of channel-locks helps, too.

-Bryan

[DieselSpider]

Sorry, I mean the rod at back of caliper with that goes into piston. I am trying to get this rod compressed enough to slip the hand brake with the key into this rod. The springs, ()()() this configuration is a heck of a strong pressure. The hand brake shaft is slotted and lines up with notch on this rod with the key slotted between so when hand brake is applied it pushes down on rod, which inturn pushes the caliper iston against the brake pad.
I might try to find a machine shop that has equipment for valve spring compression. They may have something that will work. Otherwise I don't see how anyone can DIY a rear caliper rebuild. And with the responses here, neither have most people on this forum.

Mine had a total of 5 washers each. No problem other than having to do it twice as the first time i had the rod in the wrong configuration.

Yes, there are 5 Bellevilles and 1 flat washer not 6 Bellevilles and they go in this configuration |)()(). 6 would increase how hard you'd have to pull the brake lever to set the parking brake and would require a special tool to install the brake arm. I only needed a big screwdriver to help ease things together when I did mine. Also be mindful that setting a Belleville like this )) doubles the lbs of pressure required to compress it.

Biggest issue was getting the flat o-ring to seat completely so the piston would move freely. If you have to use a c-clamp to install the piston then there is a good chance that the flat o-ring is not seated correctly in its groove.

[DieselSpider]

Sorry, I mean the rod at back of caliper with that goes into piston. I am trying to get this rod compressed enough to slip the hand brake with the key into this rod. The springs, ()()() this configuration is a heck of a strong pressure. The hand brake shaft is slotted and lines up with notch on this rod with the key slotted between so when hand brake is applied it pushes down on rod, which inturn pushes the caliper iston against the brake pad.
I might try to find a machine shop that has equipment for valve spring compression. They may have something that will work. Otherwise I don't see how anyone can DIY a rear caliper rebuild. And with the responses here, neither have most people on this forum.

Mine had a total of 5 washers each. No problem other than having to do it twice as the first time i had the rod in the wrong configuration.

Yes, there are 5 Bellevilles and 1 flat washer not 6 Bellevilles and they go in this configuration |)()(). 6 would increase how hard you'd have to pull the brake lever to set the parking brake and would require a special tool to install the brake arm. I only needed a big screwdriver to help ease things together when I did mine. Also be mindful that setting a Belleville like this )) doubles the lbs of pressure required to compress it.

Biggest issue was getting the flat o-ring to seat completely so the piston would move freely. If you have to use a c-clamp to install the piston then there is a good chance that the flat o-ring is not seated correctly in its groove.