Rebuilding Brake Calipers

[Havoc1231]

For my 77 GS750...
I currently have my front caliper broken down and will be breaking down the rear some time this week. They are both pretty cruddy and was going to soda blast and repaint them, however my manual states that they should only be cleaned with clean brake fluid. Does this mean I should not soda blast, submerge in water and then dry with compressed air? I'm assuming the point is that there shouldn't be any other type of fluid in the system other than brake fluid to prevent issues. Also, is there a special kind of paint that I should use that won't be ruined by brake fluid contact?

Also, I'm looking for a good rebuild kit that incudes the caliper dust covers (4), piston seal, piston boot and caliper axel O-rings. The only kit I have found so far is from K&L and only seems to have the piston seal and boot for the front caliper and I haven't found any kits for the rear caliper.

I was hoping not to have to spend $200 rebuilding these, however it seems to be going that way. Are there are any direct fit replacement calipers I can buy and swap out?

Also, my bike only has a single front caliper, but it has two separate brake lines joined at a junction. I believe I read I can just replace these with a single brake line, can anybody confirm this? I think the junction device is only there to allow for the addition of a second front caliper if desired.

Once again, thanks for any help you all can provide.

 

[chuck hahn]

I get the OEM stuff when it comes to whether my life depends on the bike stopping or not..but that me.

As for the line..yes you can have a single line made running directly to the caliper from the master cylinder and do away with the splitter. Under the black plastic cap on the rim youll find the hub is already drilled for the second rotor. You can get a 78 750 fork lower, disc, and caliper and add another brake if you desire. The splitter will also require a dual port banjo bolt. The splitter is in fact there for that very purpose on the 78s. they just use the same splitters on the 77s and 78s.

 

[Nessism]

Seals are available from your favorite Suzuki dealership part source, including a good many that sell over the internet. I strongly advise against K&L brake system parts. OEM Suzuki seals are superior and about the same price. Problem comes in if the pistons are pitted, since it seems Suzuki discontinued those. Often times you can find some on the used market so here's to hoping...

Soad blasting and washing the calipers in soap and water is fine. As you sumissed, the comment about only using brake fluid pertains to during a normal servicing, not during a full rebuild.

As for what paint to use, not sure. There is rattle can "caliper paint" on the market but it's not as durable as the OEM paint. Painting and then baking may be your best bet this side of something like Gunkote. I used the later on my most recent project and it has excellent chemical resistance. Don't think it's as tough as the OEM paint though.

Good luck

 

[Havoc1231]

Thanks for the quick responses. The piston on the front caliper looks flawless, I'll keep my fingers crossed for the rear pistons. I've got a pretty decent powder coat guy so maybe I'll go that route as I've done with a lot of the other parts on the bike. I'll have to ask him if that will be more resistant to stripping than paint would be.

I'm going to stick to a single front brake for now, mainly because I've already rebuilt the wheels and forks and don't want to go backwards at this point. I figured I'd just measure the two brake lines and then add an inch or so when buying the new line to allow for maneuvering etc.

 

[chuck hahn]

Be 100% sure the groove the piston seals go in are as clean as you can get them too.

 

[Havoc1231]

Thanks Chuck. The grooves are pretty gummed up, so I'll clean them as well as I can then blast them to get whatever I miss. On the topic of combining brake lines, can I do the same for replacing the rear brake line as well? I believe there are two short lines connected with a piece of metal line in between. Can I simply replace all three parts with one line? I don't see why not.

 

[chuck hahn]

I use a real small flat tip and a nut pick to clean the grooves when I do them, The nut pick gets into the corner excellently. Yes on the rear one..may need to fab a hold down somewhere though.