»  BC-BF Legacy Discussion »  Wheels, Tires and Brakes
#Brake Caliper Rebuild Write-Up

Custom Search
Login | Register




Post new topic Reply to topic  [ 4 posts ] 
Author Message
 Post subject: Brake Caliper Rebuild Write-Up
PostPosted: Thu Jul 28, 2016 8:19 pm 
Fifth Gear
Joined: Mon Nov 06, 2006 3:41 am
Posts: 8352
Location: Tenino, WA
This isn't going to be a complete how-to guide but I will show some pictures I took along the way and a couple tips to make it easier. I had never done this before and found very little information on it when searching the web. Most people don't do this anymore because rebuilt calipers are generally quite cheap. They're as cheap as $35 a side for some cars but for these calipers (05 Legacy GT) rebuilding them was significantly cheaper because rebuilt ones cost about $80 each plus $70 if you supply a core for the fronts for loaded rebuilt centric calipers from rockauto. Even more expensive from subaru or the parts store.

I don't trust someone to rebuild parts and it was cheaper to rebuild them myself and I enjoy the learning experience, so that's what I did with mine. I bought these calipers from a guy on the other legacy board and he rebuilt them for me. They didn't last long before they began sticking and stranded me on the side of the freeway with my calipers glowing red hot and a little smoke coming out of the wheels. This person clearly did not rebuild them properly. He didn't replace the pistons or hone the cylinders so the rust continued to spread and it's probable that he used grease on the seals, which may have compromised them. ONLY USE BRAKE FLUID on the seals! Other products can deteriorate the rubber in the seals and cause them to break down or swell and destroy them.




I originally thought my brake master cylinder was bad because it seemed like the brakes would stick on opposite corners of the car (ie - front left, rear right and vice versa but replacing it did not help) and I purchased a new Centric master cylinder from rockauto.

Centric Master Cylinder for SVX FWD non-abs part # 130.470.19
My ABS is gone and I had an SVX master cylinder to keep the 1 1\16" bore of the SS master cylinder. It's the only one that has the same size bore and non-abs.

Image
Image
Image




My calipers were seized so bad that 130 PSI of air pressure injected into the bleeder hole failed to removed them. I almost couldn't get them out with my own strength. I had to use a combination of a pry bar and rotating them with a channel lock pliers. I even used a 3 lb mini sledge and a punch through the bleeder hole straight to the back side of the pistons with no luck. As you can see below, the pistons were damaged pretty badly from the pliers. The damage wasn't on the sealing surfaces so I could have still used them but I bought new centric ones instead.

Image
Image
Image




Here are some pictures showing the condition of the pistons and the bore of the calipers.

Image
Image
Image
Image
Image
Image
Image
Image
Image
Image




Here you can see the seals were swollen badly. Not sure if it was from being overheated or from the person who rebuilt them using some type of grease on them.

Image
Image
Image
Image
Image
Image




You will need a cylinder honing tool like this one. I got it off amazon. Probably a Lisle tool. Pretty cheap and it goes right into a drill chuck. You coat it and the bore in some engine oil or some other lubricant and turn it on a low to medium speed while moving the tool in and out of the bore. Don't pull out all the way; just enough to cover the whole length of the bore and get an even coverage. Keep checking the bore to see if you've removed all the rust or light pitting so you know when to stop. If your bore is pitted badly, it won't work because you'll have to remove too much material and won't get a good seal when you're finished.

Image
Image
Image
Image




Evaporust works wonders removing rust. They sell it at autozone and harborfreight and online for about $25 a gallon. It's biodegradable, non toxix, no VOCs and can be reused many times. Soak it overnight and it will remove a lot of the rust leaving the rest loose enough to rub off.

Image
Image
Image




Here's a little tip that will save you some frustration. Coat the pistons and cylinders with clean brake fluid. Then insert the new seals (Don't reuse your old rubbers!). Instead of trying to put the dust seal on first, as I've seen others do or after your piston is installed, put the dust cover seal on the end of the piston that sits in the back of the cylinder as shown below. Then slide the piston in (if you did a good job on the bore and lubed everything well with brake fluid this should go right in by hand) and the seal slides up the piston as it goes deeper into the bore until it snaps onto the seat on the brake pad end of the piston and you seat the seal into the seat of the caliper. It's super easy. If, for some reason that didn't make sense, don't worry. It will when you're doing it.

Image
Image
Image




This is what it should look like when you're done.

Image
Image
Image
Image
Image




I always like to clean up my hardware with a wire wheel on a bench grinder before reinstalling parts. Then I hit them with an aerosol can of anti-seize that napa sells made by permatex I believe.

Image




Make sure to clean all the old grease off the slide pins and regrease them with some slide pin grease and put new seals and boots on them to keep you brakes from dragging or seizing up on you.

Image
Image
Image
Image

_________________
98 Metro Hatch Daily Driver :)
91 SS EJ20G Engine/Tranny/Diff Swap Build Thread Here
"Your testes are close to your bottom but you still play with them all the time." Jeremy Clarkson


Profile  Offline
Reply with quote  
 Post subject: Re: Brake Caliper Rebuild Write-Up
PostPosted: Tue Aug 02, 2016 6:07 pm 
Site Admin
Site Admin
Joined: Tue Oct 15, 2002 11:37 am
Posts: 27315
Location: Houston, Tx
Excellent write-up & pictures Kimo! And thanks for measuring the caliper piston :)

One thing I'll comment on is your comment about honing too much out of the bore. The seal isn't really made around the bore, but rather the seal itself. So if you hone too much out it could cause piston alignment/binding issues. But you'd have to hone quite a bit of material out.

I'm going to add this to the sticky compilation.

_________________
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
1997 Impreza OBS

If you need to get a hold of me please email me rather then pm


Profile  Offline
Reply with quote  
 Post subject: Re: Brake Caliper Rebuild Write-Up
PostPosted: Wed Aug 03, 2016 4:41 am 
Fifth Gear
Joined: Mon Nov 06, 2006 3:41 am
Posts: 8352
Location: Tenino, WA
Thanks Josh. That's good to know. Wish I would've taken more pictures and done a more step-by-step write-up but my main concern at the time was getting the car back on the road for the Subaru show last summer.

_________________
98 Metro Hatch Daily Driver :)
91 SS EJ20G Engine/Tranny/Diff Swap Build Thread Here
"Your testes are close to your bottom but you still play with them all the time." Jeremy Clarkson


Profile  Offline
Reply with quote  
 Post subject: Re: Brake Caliper Rebuild Write-Up
PostPosted: Tue Sep 27, 2016 9:26 pm 
In Neutral
Joined: Fri Jul 24, 2015 3:28 pm
Posts: 13
This is a great write up. I've rebuilt many 4 piston calipers and it's the same process. Sometimes it's harder with the 4 pots because the pistons are seized. Overall you did a great job and the write up is amazing.

_________________
2005 WRX
V9 Engine Swap, V7 6spd, VF37


1992 Legacy SS


Profile  Offline
Reply with quote  

Display posts from previous:  Sort by  

Post new topic Reply to topic  [ 4 posts ] 


Who is online

Users browsing this forum: No registered users and 1 guest

Panel

Top You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
Search for:
Jump to:  

Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
Dizayn Ercan Koc