Things are a little slow for winter so though I would post a topic for the fun if it.

Link to the rear rebuild post: https://www.fiero.nl/forum/Forum9/HTML/000037.html

Just for the fun of it I thought I would try to rebuild the front caliper on my 85 to see how well it would work. I want to try the rears next since they are a lot more $ then the fronts.

I know the fronts are cheap for rebuilds but wanted to see how this works and only cost $1.50 per caliper for the kit plus my time.
Did learn something interesting I did not know.

So lets get started.

Pulled the calipers and took them apart. Here are the basic parts. Don't know if I named the parts correctly but think you will know what I mean.



Popped the pistions out with air, Note to self never put you hand between the piston and caliper frame to catch it. Yhoow..!

Both pistons had some galling from something. If the rebuild does not work this will be why.



I polished both pistions with crocus cloth. Their probably now smoother than new. These are the plastic pistons no AL.



The kit just consist of the dust seal and piston seal. The piston seal sets in a groove in the bore and the dust just presses into a step on the caliper and a groove on the piston.

The pin guide "0" rings set in a groove in the pin bores.



Now here is the interesting thing I never looked at before. Had always heard that if the pins where scored you should replace them. I alway thought the pins run in the caliper bore fairly close. Turns out the pins actually run on the Pin "O" rings and do not touch the caliper other than hard braking.



Knowing that from now on when I replace pads but not calipers I will alway pull them out and clean the pin bores,pin "O" rings and pin seals before I re-lube the pins and re-install the caliper. The pin seal is also improtant to keep junk off the pin "O" rings. One was missing off my 85 which I will replace for sure.

Here is a pic of the pin oring as I reinstall it.
I then put a fair amount of pin grease in the bore hole and installed the pin while I held my finger over the other end of the bore to keep the grease in the bore and force it around the pin. The idea is that you want to completely fill the void around the pin so water will not collect next to the pin.



Going to try the rears for the fun of it now. The kits for those are about $3 each.

DR signing off.

Good Job Dodgerunner..... Excellent write up and pics !!!! They won`t allow me to give anymore A+`s or I would ...Thanks..................

Awesome write up, thanks I am getting ready to do this myself. Giving a plus for 3800superfast and myself.

A + for you. Nice write up. I tried the rear ones first and ended up scrapping the rebuild and buiying rebuilt ones.

The front ones look much easier so I will probably do them myself.

Bump for the heck of it.

Cool, have to let us know how they work when re-installed.

A couple questions...

Did you pre-lube the piston with anything before putting it back together?

How hard was it to install the seal?

Can't wait to see the rears done.

Steve

quote Originally posted by fierohoho: Cool, have to let us know how they work when re-installed. A couple questions... Did you pre-lube the piston with anything before putting it back together? How hard was it to install the seal? Can't wait to see the rears done. Steve

I first tried brake fluid but it didn't seem to be quite slick enough, so I tried the old bike racer tip and used WD40.
Seemed to work better. I might try silicone grease next time.
The piston seal just slips in the groove and is easy, however since the clearance between the piston and the bore is very small you still have to press the piston in. I used the bar clamp shown in the polish photo.


The dust seal goes in very easy. If you are carefull you can just work it in with a screwdriver since the edge is all rubber covered.

[This message has been edited by Dodgerunner (edited 12-04-2006).]

Hi Dodgerunner,

I think WD40 was a bad idea, becuase as far as I know it´s based on mineral oil. You should never ever use
mineral oil products together with brake parts. The mineral oil will cause damage to the seals.

------------------
Jürgen Martin
white GT 87
Germany

i've been trying this rebuild but i can't get the pistons to pop out. how much air pressure did you have to use to get the piston out? i have one hole in the caliper pluged with a bolt and i'm blasting air in the other. it moves very little but wont come out!

Just thought I would do a follow up since I now have 1K + miles on the calipers.

All four calipers are working great and have not had any leaks, squeaks or noise of any kind.

Life is good so far for less than $20 for rebuilding all four...