Rear Caliper Rebuild

[lane_viper]

So I've been working on rebuilding my rear Calipers on my GTS. Just figured new seals and dust boots would help, since the car turned 26 years old.

It has been kind of a nightmare. Getting them apart was easy, putting them back together... different story.

Wondering if anyone has any tips on getting the c clip to seat that holds the E brake assembly together.

Brembo_Caliper_16.jpg

Found this that has really helped...

https://wiki.seloc.org/a/How_to_Rebu...Brembo_Caliper

But for the life of me, I can't get the C clip to seat. I've been racking my brain to think of an easier way than pressing and potentially breaking things, but no luck so far.

Would hate to dish out money for new calipers due to a stupid C clip.

Thanks Guys in Advance.

[goggles Pizano]

If Tom was around he would have given you some advice. Maybe the guy in Canada who took over Tom's upgrades can help.
That's the problem with the rears. Pain to put back together.

[goggles Pizano]

Plus you are gping to get old 26 year old calipers and are back to square one.

[My98RT10]

I did a rebuild myself a few years ago but I don't remember the detail you are asking for, sorry. I am at an age now where forget a lot... and this is not a joke...

[AZTVR]

Perhaps use a circular clamp to compress the c-clip to the same diameter as the piston inner bore. A similar idea to a piston ring compressor? I picture a higher end hose clamp (aka "Jubilee clamp") that has a smooth inner surface and appropriate size; although, maybe one of the cheaper ones that are perforated through would work just as well. Compress the clip and then hold the clamped clip up to the piston and press the clip in.


Jubilee.jpg
Brembo_Caliper_24.jpg

[GTS Dean]

^this is a good idea^

Find a socket in your tool box that *just fits* inside the piston, or maybe 2, to lightly sandwich the snap ring between them. Use the hose clamp to compress the snap ring squarely and drop out the bottom socket. Set the assembly on top the piston and tap the last socket down until it seats.

[lane_viper]

So it was a pain, but I finally think I got them. I ended up using a 20 ton press to press the piston. While it was under some tension, not max tension, I rotated the piston in the same direction as you would screw the piston down. I think this help push it just enough to get the C clip to click in place.

The sucky part is there is really no way to double check to make sure its seated without taking it apart again and then you are back to square one.

I believe its seated because the piston was further down that it had been in.

The only way to maybe know its correct is to simulate the parking brake motion and see if the piston goes in and out with the arm manipulation. This is a very small movement.

I've learned a lot through this process and really don't ever want to have to do this again.

I did end up getting frustrated and ruined one of the worm gears and sheared off the retaining bolt on one of mine and had to buy a used/good rear caliper for the parts.

Couple of tips in addition to the doc listed above.

1. remove the O-rings and use heat to remove the Loctite on the O-ring bolt. It will break off as the metal is pretty soft and this bolt is required for the calipers to work properly
2. Do not go "He-man" with a press pushing the piston in. I cracked the worm gear doing this, and the way it screws down it will not just press down after a certain level. You have to maintain pressure and attempt to "screw" it down.

I wasn't for sure I could make mine work after rebuild so I order 2 more used/good calipers. If anyone needs them let me know.

Thanks for the friendly suggestions and I'm hoping this I never do this again.

[Fatboy 18]

I have done this a couple of times but took my time and luckily did not have the issues you experienced.

[40mm]

Well crap… I wish I had seen this sooner.
I’m the Canadian guy doing Toms 40mm conversions now- took me a while to figure out what made this so hard!

Turns out it’s dead easy to get the snap ring to seat, you just need to rotate the parking brake shaft as you apply some pressure on the piston. That lets it crawl down the worm gear.
It wasn’t down enough for you, which is likely why you stripped the threads with all the pressure.

I eventually milled a spacer that sits on my c-clamp, but I initially did it with a box end wrench on the spline where the parking brake arm fits, then used a couple 1”+ open end wrenches around that to give me the space to rotate the shaft and simultaneously allow a big c-clamp to squeeze the piston in, squeezing towards the wrenches.
Doesn’t hardly take any pressure while you rotate the shaft. You’ll hear a nice high metallic click as the snap ring seats.
It’s very satisfying lol.
I’d recommend first to just try pushing the piston in with your thumbs as someone rotates the shaft, you might get lucky!

Sorry I didn’t see this soon enough to help, but maybe this’ll help anyone searching this solution in the future.
Any questions or a better description best to email me at ricks40mm (at) hotmail (dot) com.
I obviously don’t creep here often enough anymore.
Rick

[FlashFyre]

Rick,

You making any more rears? I've been sending you interested owners but they had said you didn't have any more stock.

Jay

[40mm]

Hey Jay!
How goes it?
Working on it. Machining is starting up soon.
Took forever to source enough cores- seems like Covid was an excuse for no one to send me back cores so I had to scrounge enough up. Likely be ready to make some up by this fall.

[FlashFyre]

Hey Jay!
How goes it?
Working on it. Machining is starting up soon.
Took forever to source enough cores- seems like Covid was an excuse for no one to send me back cores so I had to scrounge enough up. Likely be ready to make some up by this fall.

Been good. Tracking the silver GTS a bit.

I'll likely buy a set of 40mm as spares for my GTSs. Should be able to sell a bunch right away. I know there is some pent up demand for them.