Twin caliper rebuild

topgunjames

Member
Disclaimer: I'm not a brake specialist, the method below is simply the procedure i used that worked for me. I'm not responsible if you follow this method and have brake issues.

Successfully rebuilt my evo 3 calipers,the rebuild process is slightly different to trondabrons magna single pot in the fact that theres 2 pistons not one and a retaining ring is used to hold the dust boot in its place.

Anyways this basically summarises the process with pictures

First off you have to remove ONE piston, i.e. you rebuild one piston bore at a time, making sure the other piston hasnt been pushed out of its bore compeltely
20032012461.jpg


Remove the piston, its old dust boot, retaining ring and inner seal and give it a good clean with some brake cleaner, also remove any excess grit in the dust boot groove with a flathead screwdriver lightly, making sure you dont scratch the inner bore, same time lightly polish the piston making sure its nice and smooth.
NOTE: take notice of the orientation that the old dust boot came off, as you must put the new dust boot in the same way (the dust boot varies on each side if you look closely)
20032012462.jpg


Lubricate the new inner seal with brake fluid and install it in its position, also lubricate the entire bore with some fresh brake fluid
20032012463.jpg


So far as you can see the rebuild process is the same (besides the fact that there's 2 pistons) as the single piston calipers, heres where the rebuild process differs.

Lubricate your new dust boot with brake fluid, then place it over the piston (just the front part of the piston not all the way as you can see in the pic).

20032012466.jpg


Next gently push the piston (making sure the bore and the piston is well lubricated) into the bore, make sure you do it straight and dont force it, it should go in no problem if you push it in nice and level.
20032012468.jpg


Using your fingers tuck in the dust boot surrounds so that they are just flush with the outer rim of the bore
20032012469.jpg


Now insert the retaining ring inside the bore making sure it does not go under the dust boot but rather over it, push it all the way back till it snaps into place in its groove
Below shows the retaining ring just on the outskirts of the bore (you just have to push the retaining ring further in till it snaps into the groove)
20032012470.jpg


Thats it, repeat the process with the second piston, then test the caliper for actuation and that the dust boots remain in place

note: dont push the pistons completely out, just enough to test that the pistons are properly covered by the boot, and that the retaining rings are hold the dust boots in place)

The picture below shows me testing the caliper (i had a sanding block placed horizonatally to stop the two pistons coming out completely but removed it for photo sake)
20032012471.jpg
 
Got the kit from henry for 85, but you could possible get the kit much cheaper if you go to a part stores or brake specialist and requiest a rebuild kit for a magna twin caliper (model with abs) or even the pajero NH or NJ which use the same seal kit
 
thanks for answering James

First caliper i actually done it wrong i did it same method you done yours method and realised that the retaining ring wasnt "retaining" anything, this method took me an hour for one caliper (pushing the piston while making sure the boot was going in evenly was the culprit), then i used a diff method (the one written here)for putting the dust boot on which made the retaining ring serve its purpose, this took me just over half an hour for one caliper, then i redone the first caliper and took a little less time maybe 25 mins as i knew what i was doing.

So altogether, 2 hours as i screwed up the first time.
 
Ive done this too many times.
Be careful of the advice you give people on rebuilding brake calipers. Especially when this is your first time doing it.
Maybe a disclaimer should be advised.

Piston goes into first.
You dont need to put the piston and the rubber boot in at the same time. Its a waste of time.
Just put the boot on afterward.
When you press it on it will lodge itself in the gap.
C-clip goes on last. You must make sure the clip is inserted properly into the boot so the boot is well retained and not misaligned

As I advised James they have the same piston size as Verada ABS you may use that seal kit.
He didnt even know for sure what calipers he had and wasnt convinced they were EVO3 size even after I reassured him they were.
Like why would I sell you a seal kit if i know it wont suit your calipers. Does it look like i rip people off alot on here?
It is the same part number I have part numbers for all the smaller twin or larger twin piston caliper.
Same part number means same price.
Its reason for the price tag is the its a twin piston caliper. 4x seals and 4x boots.
But sure Ive given you good information you can do whatever you want with it.
I gave you an excellent deal with excellent service and advice. :roll:
I doubt you or anyone can walk in a shop and buy that seal kit for cheaper. Or maybe you got the hook ups. :roll:
 
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