Caliper rebuild question

[KA1J]

I'm getting inspired by the warm weather to get the XJ11 on the road. I just ordered the rebuild kits for the front & back calipers and have another question as to what is important to do. There's the top part of the front caliper & the bottom part. I'm not sure what the top part is called but it's the part held in place by slide pin 12.24 that has the two boots (15.27) on it in the blow-up below.

Is it important I remove/clean this part for any reason or is it just as well to leave it alone?

Thanks

[natemoen]

I believe that is the pivot pin, so pull it and clean it. In fact pull everything and clean it! Gotta remember, your life depends on the brakes working

[TomRodgers]

2nd on Nate!!!!

Pull EVERYTHING apart....spray, wipe, spray, wipe...use cheap dental picks to clean ALLLL grooves (especiallyl behind the piston seal). fluid over time cruds up and its amazing the places where it will gum up. Then apply a thin coating of a good brake grease on the pivot pins. inspect the piston for defects/pitting. if bad, replace. lube seals with new fluid and re-assemble. Any questions, ask!!! I did all 3 calipers in about 1.5 hours....that included take off and install on bike..... bleeding the front brakes... took another 3 days!!!! LOL

[Smash]

Tom's got you covered! You really only want to do it once, so take your time and do it right.

[TomRodgers]

While you have them off, its also a good time to shoot them with a nice new coat of paint......really easy to do when NOT on the bike!!

[Erik the Red]

bleeding the front brakes... took another 3 days!!!! LOL

Look into Speed Bleeders. They have a one way valve which makes the whole process WAY easier. --> http://www.speedbleeder.com/

Dental picks: great thing to have in your tool box! I got a couple sets by just going to a dentist's office and asking for their old picks. They just throw them out after they get used up anyhow.

[TomRodgers]

i have the speed bleeders, but from complete brake system replacement, too much air in them for them to work properly.....afterwards, they work GREAT!!!!

[KA1J]

Thanks much for the info. I'll pull & clean them today, the pins are really stuck in there. Hope I don't ruin the boots on each side getting the pins out. I'll spray the pins & boots with lube before knocking them free.

Funny, the right caliper was in really decent shape, piston was as new & not much crud on any moving part. The left though was a mess. I had so much stuff to pick free. The grooves for the O-rings were thick with cement-like sediment & varnish was everywhere. It took a really long time to clean all the foreign stuff out of the well.

And yes, I'd planned on painting the calipers! Just bought 2 cans of PJ1 paint & will spray when the temp is 70 or better. I'm going to touch up paint wherever it needs it. Fortunately most of the paint on the bike is intact.

[Smash]

Ha, the piston in our front left caliper was almost completely STUCK!

[KA1J]

Ha, the piston in our front left caliper was almost completely STUCK!

Yeah, was the same here. the amount of cra% in the bore was amazing, it was jamming the piston. Someone in the past had tried pulling the piston out with pliers or something. Only affected the most outer part of the piston, not the part that is in the well.

Ugh...

[cywelchjr]

Pull EVERYTHING apart....spray, wipe, spray, wipe...use cheap dental picks to clean ALLLL grooves (especiallyl behind the piston seal). fluid over time cruds up and its amazing the places where it will gum up. Then apply a thin coating of a good brake grease on the pivot pins. inspect the piston for defects/pitting. if bad, replace. lube seals with new fluid and re-assemble. Any questions, ask!!! I did all 3 calipers in about 1.5 hours....that included take off and install on bike..... bleeding the front brakes... took another 3 days!!!! LOL

You guys are such sissies! I've done nothing to my brakes but change the pads and bleed them.

Yes, actually true, but I'm lucky because my brakes work really really well, no drag, the fluid was nice and clean, clearly well maintained when I got it, and I have continued to do so, and I do a full complete fluid exchange every year (maybe overkill, but my system is NOT going to build up crud in it on MY watch ). I am planning on SS hoses though, and while they may cost more I'm checking to see if my galfer make line for our bikes, if so my local shop can get the front lines for $120 for the 3 line set or $90 for a 2 line set (which he tried to talk me in to cause it would save me money). I'd rather spend a little more and keep the guy in business, he's got a full service shop, that services bikes back into the 70's and they understand them, although they specialize in wings. If galfer does make lines for our bikes, might anybody be interested in a possible group buy? It would bring the price down (I'm not sure how much but some I'm sure, and I understand that generally if they've ever made a line for a machine they keep the specs on hand cause they hand make all their lines so they can still make them to order as needed). They make them in lots of different colors as well, and I understand that if they don't have a standard set, with the specs they could probably make them especially if several were interested in them, and they are nice looking lines.

[KA1J]

LOL Sissies... Well if it'll help me out I'll give most anything a try.

I've been going over these calipers with a fine toothed pick & have been scraping & needling off all the old loose paint & crud so I can repaint them. I just went & got some brake lube for the calipers & will spray them tonight.

A couple of things I noticed; the smaller sliding pin that has the boots on it is really pitted badly inside. I looked to see if I could find replacements for it but came up empty. MikesXS doesn't support the XS1100LH which uses the same part 4W1-25914-00-00

These are the bikes it is found on

RX50K 1983 50 RX50 50 Special Street
RX50L 1984 50 RX50 50 Special Street
RX50MK 1983 50 RX50 Midnight Special Street
XJ1100J 1982 1100 XJ1100 Street
XJ550H 1981 550 XJ550 Maxim Street
XJ550J 1982 550 XJ550 Maxim Street
XJ550K 1983 550 XJ550 Maxim Street
XJ550RJ 1982 550 XJ550R Seca Street
XJ550RK 1983 550 XJ550R Seca Street
XJ750RH 1981 750 XJ750R Seca Street
XJ750RJ 1982 750 XJ750R Seca Street
XJ750RK 1983 750 XJ750R Seca Street
XS1100LH 1981 1100 XS1100L Midnight Special Street
XV920J 1982 920 XV920 Street

So I removed the top rust on the slider by putting it in a drill press & used a file to knock off the high spots, then steel wooled it to a shine. Still though, both the left & right sliders are very pitted and the lube will inevitably escape from the boots because of this.

I thought about putting some JB weld on it and then filing it down again with the idea the weld would fill in the pits & I'd do the drill press thing again and make it a solid rod with the pits filled by jb weld but I'm not sure how that would hold up & if some of those filled potholes would break free & cause different problems at that time.

Any better ideas what to do with these pitted sliders?

Also, does the brake lube go on the face of the shims only or does it go on both sides of the shims? My left side shim was missing; since I only have one brake pad shim would I be well off as was suggested, to form a shim out of a soda can & put it on the left side pad that was missing one?

And does the brake lube go on both sides of this shim or just the side facing the pad? If I don't make a shim for it, I guess I'd just put lube between the piston & pad?

Thanks!

[brcree]

Brakes

I had some pistons that were realy stuck, I used a grease gun to pop them out. Open the bleed nip., use a bolt that fits where the brake line goes and block it off. Put the grease gun on the bleed nip and pump. Piston comes out with ease. Since there is break fluid in this area the grease is easy to remove.

[KA1J]

The left was really stuck hard but I managed to get it out. I spent a few hours probing out the hardened sediment that was in the wells & especially in the races for the O-rings. Finally got that all done, the holes plugged with blue masking tape & I'm painting them today.

I should be getting the new o-rings in today or tomorrow but those smaller sliding pins are really pitted and probably need to be replaced. They'll work for the time being & I'll just have to replace them later if I ever find new ones. If I can't find new ones, I'll just try my idea of filling the pits in with jb weld & reshaping them as I mentioned above.

[crazy steve]

...So I removed the top rust on the slider by putting it in a drill press & used a file to knock off the high spots, then steel wooled it to a shine. Still though, both the left & right sliders are very pitted and the lube will inevitably escape from the boots because of this.

I thought about putting some JB weld on it and then filing it down again with the idea the weld would fill in the pits & I'd do the drill press thing again and make it a solid rod with the pits filled by jb weld but I'm not sure how that would hold up & if some of those filled potholes would break free & cause different problems at that time.

Any better ideas what to do with these pitted sliders?

Also, does the brake lube go on the face of the shims only or does it go on both sides of the shims? My left side shim was missing; since I only have one brake pad shim would I be well off as was suggested, to form a shim out of a soda can & put it on the left side pad that was missing one?

And does the brake lube go on both sides of this shim or just the side facing the pad? If I don't make a shim for it, I guess I'd just put lube between the piston & pad?

Thanks!

The pitting on the pins won't hurt anything as long as you clean the rust off; media blast them or chemically remove the rust, then use something to help prevent its coming back (paint or something). If you feel the need to fill the pits, do it with metal (brazing, welding) but you'll have to remachine the pins. Like you said, if the JB Weld pops out, that could jam them...

Brake lube... bit of confusion here. For 'brake lube', a product like this is what you need: http://cgi.ebay.com/ebaymotors/Penri...Q5fAccessories. This is safe to use on all of the rubber parts, and is used by the OEM manufacturers. Use this on the slider pins, and on all the internal rubber parts; it's compatible with all brake fluids, and will help keep moisture out of the piston seal grooves, as well as making assembly much easier. I pack the seal grooves with this before installing them.

The 'brake lube' you'd use on pads is a much different product. While partially a lube to help prevent sqeal, it's also supposed to be a semi heat shield. That's the main purpose for the steel shims; to be a heat shield. Under 'normal' braking conditions, if you don't build excessive heat in the brakes they're not really needed (which is why when they're missing, it's no big deal). If you feel that you need/want the shims, then make them out of .005" stainless steel shim stock, not aluminum. Aluminum is an excellent heat conductor (that's why most pots/pans are made with it) and will defeat the purpose of them, as well as the soft aluminum wearing rapidly. Stainless reflects the heat much better. If you use the pad 'lube', a thin coating between all the parts won't hurt.

This help?