Front caliper rebuild question

[Under Dog]

I just bought a rebuild kit for my front caliper. Everything looks right, except the seal between the caliper and piston doesn't have the little ridge that rides in the caliper housing. The replacement looks more like a squared off o-ring whereas the original had that extra line molded around the outer circumference.

Does that little extra rib in the seal really matter? Or do most rebuild kits look like the one I bought?

Thanks all! This is my first brake rebuild and I just want to make sure I get it right - brakes matter!

Doug
Portland, OR
'79-'80 XS400 "Frankenstein" (pieced together from dead parts...)

 

[arfstrom]

http://www.xs400.com/forum/showthread.php?t=7148

I found this spot, Drewpy had a great picture inserted, I think answers the question. I remember when I did mine, I had to do both the MC, and the actual brake piston due to the Years of not being used. This next thread has a good photo of the parts, granted he is looking for the rear MC. I am willing to bet cha the differences are nominal.
http://www.xs400.com/forum/showthread.php?t=8175

by the way, dont forget to add your bike info when starting a thread, my guesses are truely guesses, I just added my info to a signature so I forget....
Tobie

 

[Under Dog]

Tobie,

I appreciate your finding those posts. They are a good reminder to be careful when I put the master cylinder back together and will come in handy then.

However, it's the seal in the front caliper itself that I'm worried about. The new one looks to be the right size, it just that little outer ridge that seats in the circumference of the caliper body. I'm guessing it'll be fine, as I've not found any complaints about the seals online.

I just don't want to mess this up - I'm hoping to teach my son and daughter how to ride the thing.

Doug
Portland, OR
'79-'80 XS400 "Frankenstein"

 

[arfstrom]

Yea, your right pay attention to details I did it both last year, and the most significant thing I remember was to "block the piston before increasing airpressure to blow out the piston. after that everything else was easy. I had used a "shipping air bag" you something I recieved via mail, came with an air pillow. when the piston came out, the resulting pop of the air pillow, and the thought if I hadnt put nothing there, that piston would have gone sailing. Good luck

 

[jmd_forest]

Polish up the caliper and the piston with some fine grit wet/dry paper to eliminate any/all rust. Clean thoroughly and and wet them up with clean brake fluid before reassembly. Keep the piston seal from twisting when installing onto piston and install piston into caliper. You should be fine. The extra line "molded" around the o-ring was probably formed from years of pressure in the caliper.