XS 400 FRONT BRAKE CALIPER PROBLEM

[SgtPepper519]

I have been viewing the site for a while now and I just want to thank you all the help you have given me. I have been trying really hard to get my xs400 roadworthy and with the help of this site, I am just about there.

The last issue I am having is my front brake is binding (the wheel does not spin freely when lifted off the ground) however it is still functioning because when I pull the brake lever I feel pressure and can see movement in the caliper and the pads move closer to the disc preventing the wheel from spinning.

The problem is that for the life of me I cannot figure out which is the caliper slide pin. The caliper attaches to the caliper mount through a bolt that passes vertically through the caliper into the mount. I am unsure if this is what causes the caliper to float freely as I have never seen a vertical caliper slide pin before and it doesn't really make sense to me. I would like to figure this out before I rebuild the caliper in case this easy task solves the problem. If anybody has any advice for me or has worked on one of these bikes before I would really appreciate some help. THANKS

[HoughMade]

If I were you, I'd go ahead and take the caliper off and disassemble it, including removing the piston. Clean everything and then reassemble with out a rebuild kit. All the rebuild kit contains is the piston "O" ring (seal) and a cap for the bleed screw. Just try cleaning everything and then flush the brake fluid. My bet is on rust or crap around the piston itself- that's what was going on with mine and i had the same issue.

[mike1949]

I have been viewing the site for a while without making any posts (it seems any question I had have already been answered) and I just want to thank you all the help you have given me. I have been trying really hard to get my '81 xs400 roadworthy and with the help of this site, I am just about there.

The last issue I am having is my front brake is binding (the wheel does not spin freely when lifted off the ground) however it is still functioning because when I pull the brake lever I feel pressure and can see movement in the caliper and the pads move closer to the disc preventing the wheel from spinning.

I am aware that most likely some rust or dirt has got into the caliper and is preventing the piston from returning all the way in but before I go ahead and clean and rebuild the whole caliper I thought I would just grease up the caliper slide pin and see if I can get the caliper to float freely on the disc because perhaps it has dried up and is preventing the caliper from sliding freely.

The problem is that for the life of me I cannot figure out which is the caliper slide pin. The caliper attaches to the caliper mount through a bolt that passes vertically through the caliper into the mount. I am a little unsure if this is what causes the caliper to float freely as I have never seen a vertical caliper slide pin before and it doesn't really make sense to me. I would like to figure this out before I rebuild the caliper in case this easy task solves the problem. If anybody has any advice for me or has worked on one of these bikes before I would really appreciate some help. THANKS

Hi SgtPepper519

If you have been viewing this site for a while, surely you must be aware of the protocol of introducing yourself to this forum. ie: My name is, I come from, my bikes are, my interests are.

You have mentioned the word "caliper" 13 times, I think we get the gist of your problem.

I have had a very similar problem to you. I might just reveal my solution if you adhere to the above protocol.

[SgtPepper519]

Hi SgtPepper519

If you have been viewing this site for a while, surely you must be aware of the protocol of introducing yourself to this forum. ie: My name is, I come from, my bikes are, my interests are.

You have mentioned the word "caliper" 13 times, I think we get the gist of your problem.

I have had a very similar problem to you. I might just reveal my solution if you adhere to the above protocol.

Hey Mike1949,

I apologize. That was rude of me.

As you know, my name is SgtPepper (I am a big Beatles fan). I have always really enjoyed working on cars but just recently was bit by the "motorcycle bug" and I can't stop thinking about riding. I am still new to bikes and this forum but I look forward to helping out where I can.

[mike1949]

Welcome to the forum Sarge.

The problem I had with my bike a few years ago was that every time I applied the front brake they would seize up for a couple of minutes then free themselves when cooled.

I took it to a good bike repairer and all the problem were was old brake fluid. He changed the fluid, caliper seals and bled the brakes and the problem was sorted.

Re-reading your post i'm not to sure if it is the same problem as yours.

Regards Mike. (Who lived in a black submarine not a yellow one)

[drewpy]

there were 2 different types of caliper used in the xs400.

1 was a floating caliper design (common)

and the other used a sliding pin design.

let me know which one you have! (or post a pikkie)

[SgtPepper519]

there were 2 different types of caliper used in the xs400.

1 was a floating caliper design (common)

and the other used a sliding pin design.

let me know which one you have! (or post a pikkie)

Thanks for your response. I can not figure out how to post a picture to the forum so here are 2 links.

http://www.flickr.com/photos/52806761@N04/4869435969/

http://www.flickr.com/photos/52806761@N04/4869436235/

The Haynes manual I have does not cover this model. In the model they cover there is a sliding pin that goes horizontally through the caliper into the mounting bracket.

[drewpy]

you've got the unusual version.

this is a swinging caliper and was fitted to the rd400 daytona model (us version) there is a thread on this very caliper somewhere.

HERE

[Ficky]

you've got the unusual version.

this is a swinging caliper and was fitted to the rd400 daytona model (us version) there is a thread on this very caliper somewhere.

HERE

Hi Team

Yes I have the same one on my XS400 that spent time in the USA, I just gave it a clean new fluid and it all work fine, geting the shoes to sit right when replacing the wheel can be a little tricky but not a big problem, finding new shoes was not hard, (when I first lade eyes on it I thort it had worn at a strange angle but no they come like that sure theres a resson.

Cheers Chris

[OllieB]

Thanks for your response. I can not figure out how to post a picture to the forum so here are 2 links.

http://www.flickr.com/photos/52806761@N04/4869435969/

http://www.flickr.com/photos/52806761@N04/4869436235/

Same caliper that's on my '80 XS400 Special and original to the bike. When I viewed the edge of the pads I thought I needed new ones because the lining looked thin. Bought a new set and when I looked at the new pads saw that the lining was wedge shaped. Never seen this design before.

[SgtPepper519]

Thanks everybody for your help. Today I will be flushing all the old fluid out and bleeding the brakes..hopefully once is this done I will be able to push the piston back in all the way.

If I am unable to I will assume its because there is lots of crud built up around the piston so I will be taking the caliper apart to clean and replace the seals. I will leave an update later to help anyone who might be having the same problem.

Thanks again everybody for your help.