XS650 Special - Squeaking Front Disc Pads

[Paul Sutton]

I installed new EBC pads, aha you say! I have done quite a lot of research already but have failed to solve the squeaking. If I jack the bike up and hand turn the front wheel, either fast or very slowly, the pads make a constant squeak. I thoroughly cleaned the brake calipers and chamfered the brake pads before installation.

When I rotate the front wheel the constant squeak is coming from the left pad. If I carefully put my fingers between the caliper and wheel and gently touch the left pad the squeak stops. The squeak went away for about five minutes when riding after having slightly bent the left shim plate. The squeak stops if the brake is applied very lightly.

Any suggestions as to what to try next???

Also, what is the purpose of that screw (Item #5) that goes into the left side of the caliper and fits into a hole in the left brake pad???

Thank you.

 

[5twins]

After a few hundred miles, my aftermarket pads started squealing too. Apparently, squealing was a problem because Yamaha took several steps over the years to try and fix it. The first "fix" was what they called "anti-squeal type " retainers. These are the little chrome pieces that fit in front of and behind the caliper in it's bracket. To make them "anti-squeal", Yamaha glued little squares of thin rubber in them .....

You only need one of these and it should be installed on the front side. That way, the caliper pushes against it when you apply the brake. I tried this "fix" on mine but it didn't help. Their next "fix" was sheet metal shims behind each pad. You can see them in this drawing, parts 12 and 13 .....



You can't buy them anymore but I managed to scrounge some from a spare caliper. These fixed my squeal. I did smear them with high temp grease before installing and that may also be helping. I used the Sta-Lube Premium Red grease that 3M from Vintage Brake recommends for brake work.

http://www.autohausaz.com/pn/CI-SL3191

 

[Paul Sutton]

Thank you 5twins. I do not think I have the rubber retainers on mine but will check. I do have the shims fitted but clearly not working. I have tried the high temperature grease and that did not work but may try putting a spot of silicone sealant behind them which I saw recommended on this forum: Too much silicone and they will be very difficult to remove later on.

It is raining today so will check the retainers and even replace the rubber with new if necessary, then grease, then silicone etc.

 

[gggGary]

Probably opening myself to the curse of squealing; but haven't had an XS squeal yet. Never used grease or silicone or that kind of stuff yet either. Remember a few old Honda's that wouldn't stop squealing. Perhaps it's that I usually use some 240 grit on a DA sander and sand the rotors til any scoring is gone when I do the overhaul? My work bench has a hole with a 1/2" nut welded under it. I slap a wheel on that with spacers nuts and a chunk of threaded rod so it spins freely, bolt a rotor on it and start sanding. Flip the rotor and get the back side also, clean with solvent done.

 

[DogBunny]

I do not recommend sealant. Silicone lubricant, such as Sil-Glyde, which is specifically made for brake calipers (lots of other applications too), applied to the back of the pads and shims is fine, but sealant is asking for trouble in my opinion..
All the parts are supposed to float freely. Aftermarket pads are sometimes a little too big, and wedge tightly into the caliper -- this is wrong, they should be able to move. This might be your problem, if so file the notches of the pads a little.
The purpose of screw #5 that you asked about is to retain the pad while still allowing it to move freely. Make sure the screw that you use is compatible with the pad that you use. The screws that come in MikesXS rebuild kits are different from the stock screws, and are intended for MikesXS pads which have a different size retaining hole in them.
Also, make sure the caliper sleeve moves within the caliper boot, parts 7 and 8 in the diagram 5twins posted. I polish the sleeve, clean out the boot, and then pack the ends of the boot with Sil-Glyde before re-inserting the sleeve. Make sure the boot looks right. I have seen MikesXS aftermarket boots literally swell to twice their original size.

 

[gggGary]

Has the caliper been rebuilt? the slide DB mentions and a piston that isn't moving freely could create problems as well.

 

[Paul Sutton]

gggGary and DogBunny, thank you for the extra suggestions.

I never had an issue with squeal on the RD250B or XS1B when I had them years ago. I have never had this trouble with cars. I checked the caliper again today and it is fitted with the rubber padded retainer. I rebuild the caliper and thoroughly cleaned everything recently. As far as the caliper moving, it does but there is quite a lot of drag from the grease - perhaps a polish is in order and a lower viscosity grease. The slave piston does move freely also. The EBC pads fit very loosely and and I had wondered if this was the issue but can confirm it is not as the squealing continued after packing them tighter with PVC tape. All items on the caliper are stock and the screw does fit correctly

I am going to do the following, first I will polish and clean the sleeve and boot and apply a lower viscosity grease so that it slides very easily. If this fails I will then sand the rotor and clean with solvent.

Will attempt the cleaning tonight and report back - Thank you.

 

[DogBunny]

The sleeve simply needs to be able to move in the boot, it doesn't really have to move "freely," i.e. if it takes a little force to move it that's okay.
I am at a loss regarding your problem if what you hear is really a high-pitched squeal. You say it happens when you jack the bike and turn the wheel by hand -- are you hearing a scrape, rather than a squeak?
Squeals normally only happen when you brake, not "all the time." Do you still have the old rubber brake lines? Sounds like maybe your brakes aren't releasing, which can be caused by rubber brake lines or a gunked-up master cylinder. Grasping at straws here.

Will add that there is nothing wrong with loose pads. I don't like the idea of tightening them with PVC tape for the same reason that I don't like the idea of using sealant on them. My pads are so loose that they audibly rattle when I shut the bike off and coast, but they work just fine and never squeal.

 

[gggGary]

Good point DB; some odd assembly method may not have the rotor centered in the caliper slot.....

 

[5twins]

This is one of the reasons I'm favoring stock pads more and more. They work well and don't squeal, at least mine didn't.

 

[Paul Sutton]

The squeal is continuous when riding unless braking or touching the brake lever very softly. The sound is very resonant rather than rubbing/scraping. The PVC tape was just an experiment and was then removed. I have already checked for something contacting or out of alignment but all is correct. When hand spinning the wheel and touching the left pad gently the squeal stops.

I have been slaving away for the last 2 hours. The caliper is now sliding smoothly but the squeal continues when tested in the garage. So I attacked the left side of the rotor with 280 grit by hand sanding and it would not touch the metal at all, nor would 180 or 120 grit. I have some high quality Bosch 80 grit and it got me into the metal quite quickly. After the first light sand the squeal had stopped when tested by hand spinning the wheel. I continued gently sanding for another 20 minutes and seem to have broken through any glazing on the rotor. Tomorrow I will return to finer papers and finish the job off on both sides of the rotor and hopefully do a test run - weather permitting. As it stands I cannot get any squeal by spinning the wheel by hand now so must do the road test but the weather has not been very good for testing front brakes - damp and hovering around 0°C.

 

[Paul Sutton]

I just returned from a bike ride and all squealing has stopped. Sanding the rotor as suggested by gggGary seems to have done the trick. I assume the rotor must have got glazed by the previous disc pads.

Thanks Guys.

 

[Paul Sutton]

Update - The squealing returned soon after sanding. I have since traced the squeal to a shim which has lost all its spring. It is the one that sits behind both pads and is barely visible through the pad thickness viewing hole in the caliper. It kind of looks like a giraffe that has fallen over ice skating - must order a complete new set of shims. I bent the shim a bit and the squeal has nearly completely stopped.

Thank you for all the suggestion provided - None of then will be wasted!

 

[MaxPete]

Well, it's great that Paul seems to have fixed his squeal.

I can tell you that the auto industry finds brake squeal to be one of the most common and challenging customer complaints to fix. It really amounts to vibration between the pad and the rotor or the piston andnso some sort of gooey stuff or a spring is the usual solution.