GS750E Brake Rebuild

[Drummert]

Everything came in on friday, so I had some time this weekend to work on the bike. Brake calipers are of, cleaned (wiped, brake cleaner, sand paper for the outside, dremel to really clean and polish the insides) and painted, with today some more paint so the square bit on the back is also black (cardboard always comes in handy).

Also, I removed the master cylinder and brake lever today, together with the last brake lines. That was a lot easier than I imagined before, but I did see my brake light switch has seen better days. Thinking about upgrading to a hydraulic brake light switch, since we are doing this now anyway...

[standswithabeer]

belgium, or australia?

[Drummert]

belgium, or australia?

Haha XD, something definitely went wrong there. Will post some Belgium orientated pictures tomorrow!

[Nessism]

Nice work! Keep going...

[GSXR7ED]

Nice work indeed. You're going to need patience taking the Piston out...I gouged the crap out of mine and just ordered new OEMs. Lots of gunk build up and those tiny holes in the master cylinder will have you using a magnifying glass and light to see them.


Ed

[Drummert]

You're going to need patience taking the Piston out...I gouged the crap out of mine and just ordered new OEMs.

Actually, that went quite easy as soon as I put enough brake fluid in and just pushed them out like that. Yes, it screwed up the paint of the calipers, but they had a 40 year old paint job on them... I guess they were due for a new layer of protection anyway.

Ok, I promised some Belgium orientated pictures!

Brake Calipers masked up






Painting process




Second day of painting, decided I wanted the squares on the back to be painted as well (fun note: I had to take the newspaper of first :P)




Taking apart the master cylinder, I found this when I pulled the lever. Ouch! Guess how all the muckus came in.




Jup. Muckus.




I'm working on the parts on the balcony, little heater up, since this is our situation right now.




And I had to buy myself some circlip pliers. Guess I will need those more often anyway. Let's hope next week those are in, then its cleaning and build up again.

I'm excited, since after that I will be able to finally tune the engine and then start driving again, after more than a year being bikeless... Battery is already hooked up to the trickle charger and got the parts to tune it lying around close as well.

[standswithabeer]

lookin' good! nice work,
bp

[Drummert]

And here's the end result of the painting! Cured and all, my girlfriend didn't even mind me curing them in the oven ^^

Now unfortunately, I bought some circlip pliers online, but they got lost in transport... So I'm now for the time being stuck on pulling the master cylinder piston out...

[Drummert]

The pliers came in, so today it was time to pull the piston out of the master cylinder and clean all the parts. Originally, I had the naive idea I would be able to put everything back together today... That didn't quite work out.

Cleaning everything was easy enough. But then the master cylinder... No circlip visible in the hole where the piston is. I start worrying, thinking the little holes you can grab it at rusted off (would be my kind of luck). I spent nearly an hour carefully scratching of dirt and rust to come to the conclusion that I definitely see no circlip, nor the holes to grab it.



I decide to put the small screwdriver in sideways and wiggle around. Something comes loose!.... A white plastic ring... never saw that on a diagram.
I look again.... Again no circlip visible.



After scratching away at the dirt and rust I finally find something that looks like a circlip at first.... but its a metal wire. Also never seen on a diagram.




I start to doubt myself at this point. Do I have the right diagram? Did I even order the right replacement parts. Who will know... Then finally, after scratching away for another hour, I find the circlip, completely clogged up in such a way that the holes to remove seemed to be part of the housing. I try and put the pliers in... pliers are to wide. Time for the dremel then... Spent at least 45 minutes grinding the pliers to a fit. Total time to pull the piston out: 2,5 hours...

Needless to say, I didn't put things together after that. Actually, the piston jumped out with a push from the bottom, leaving me to figure out how the parts where in there, luckily the parts left an imprint on the rubbers, so I should be able to figure that out relatively easy.

Me little cleaning setup in the living room, since weather outside is not my favorite:

Start



Two hours in (not counting the extra time for the master cylinder piston..)

[GSXR7ED]

^^OMG!

Brings back memories of my rebuild.

Ed

[Drummert]

I think I figured it out regarding that plastic ring and metal wire: I believe they should go on the outside of the rubber seal you put on top of the piston, so that the seal stays put. I wouldn't exactly know from taking the whole thing apart, the old seal was completely torn already. No way to see if they were originally on the outside, but I believe the exploded diagram in the manual shows it like this and it does make some sense.

I also don't fully rule out someone before me screwing this up and putting it back together completely wrong...

[Drummert]

Pops up another question as well... Rebuilding the calipers now. How do you guys fit the dust cover around the outer lip where it stays against the caliper? I see how it grips the piston, but I can't seem to get the little lip of the seal around the tiny edge where it should catch...

[Drummert]

Found my answer, to whom it might concern:

1. put the piston seal in
2. put the piston in, but not fully
3. put the dust seal on the piston and let it fall in the groove on the piston
4. let the piston slide in the piston barrel
5. the dust seal now kinda stays in place because of the piston, gently go around with your fingers.

Worked for me. Still a pain in the a**.

[Drummert]

Brake calipers are together again. Started on rebuilding the master cylinder today. Obviously I ran into something: the circlip thats was put with the new piston cup set was too small.... First of all I thought I just couldn't get it in. Went to a shop in town thinking they might succeed since they do it way more often than I do. After 5 minutes of puzzling around, the guy goes: 'Dudes gave you too small a circlip man...'

Seemed to be the same size as the other one though, but I can push it down with my fingers, which I guess I shouldn't be able too. Also, the piston is able to push it out again, that's more problematic...

Can I bend the circlip, making it a little wider? Otherwise I guess I'll just have to go search the stores for a collection of circlips.

[cowboyup3371]

What kind of circlip pliers are you using - inside or outside? Some kinds of circlips will need to be pulled apart instead of squeezed together