Hi All, I've got a 1985 Yamaha SR250 with drum brakes front and rear. I've noticed something weird in that after it has rained, the brakes will make a sqeal and really bite, causing a shock to the suspension. After a little while this subsides, so usually I brake very gently as I go down the driveway and a short way up the road, and then the brakes will be back to normal. It's as is water has gotten into the drum somehow, but this still happens when the bike is under shelter, ie in my garage. Does anyone know what to do about this? Is it possible that the drums are not sealed properly and the pads are somehow absorbing water from humid air? Thanks, -- Mark
Use them very strongly occasionally to remove any glazing on the shoes, alternatively use some sandpaper on them to the same effect. Boxer
Every vehicle I've ever owned with front drum brakes[1] has been like that - I think it's due to condensation inside the drums. My Datsun ute was the worst, because it had a vaccum brake booster. Leaving home on rainy mornings it would always lock up the brakes at the first application, howerver slowly you were going or how gently you applied them. It was generally OK once it'd thrown its little tantrum though. My current truck[2] has disks at the front, but I still notice a little bit of "grabbiness" from the rear drums when using the brakes for the first time on a wet day. My advice is to be aware that it's going to happen, and be prepared for it. It sounds like you've already got that one covered though. ;-) BTH [1] 1966 VW Beetle, 1977 Datsun LWB ute, 2 x Honda CT90 [2] 1989 Ford Econovan LWB
In aus.motorcycles on 17 Feb 2007 18:41:19 -0800 back to normal as in useless? Or was that just my SR250.... None of my drum brakes squeal in the wet, and I don't recall the SR doing it. Perhaps you need to rough up the shoes some? They do all sometimes bite, that tends to be an adjustment thing. Except for the Old Girl's front 4LS which apparently is designed to do it. Zebee
Yup, rust. most (all)drum brakes have cast iron, shrunk in liners and these rust very quickly. It is only a light coating of rust that takes a couple of brake applications to polish off, and makes the brakes "Grabby" for the first couple of uses. The squealing could be just an effect of the rust or a bit of dust in the drum. This is normal for a drum brake. You may like to pull the front wheel out and blow the dust out, be careful not to breath in the dust, wear a mask as old type brake linings were made of asbestos but I doubt if a 1985 model bike will have linings made of this, best to be careful though. While you have the brake out, just check how thick the linings are, the linings should be about 3 m.m. thick. Have a look for any part of the actual shoe touching the inside of the drum. I wonder if the brake has ever had a new set of shoes? Have fun. ...
Very interesting. Thanks everyone for the answers, it's good to know there's not a serious problem with the brakes. Zebee - I've found the braking pretty good overall. I did an advanced riders course and where they give you benchmarks for stopping and I was meeting them which was good to know given some of the disc- equipped bikes weren't. Do you still have an SR? Once when I was riding home in heavy rain, I put the rear brake on and it locked on, making me go for a slide (was lucky it wasn't worse) and then having to remove the heavily bent brake pushrod to be able to get the bike wheeling again. I wonder now whether that was an extreme case of the condensation/rust thing... Cheers all, -- Mark
In aus.motorcycles on 19 Feb 2007 12:45:22 -0800 No, I only had it for a year or so. The brakes on that one were truly awful and no amount of adjusting would help. Cheap and nasty. Zebee
What he said and also lubricate the Brake cam actuator carefully with some Moly Grease on it's lobes and though the housing.Clean off all excess so none can ever get on the shoes etc. Also chamfer the leading edges when you take the glaze off the shoes and make sure your Rear brake actuator arm is fully free and lubricated to release the brakes. HTH
I posted this reply with a graphics file in it and it did not seem to show in some newsreaders, is this usual? why did it not show with the pic. Thanks. FOG. "Once when I was riding home in heavy rain, I put the rear brake on and This sounds a bit more dramatic, the brake should not lock on like that, you weren't jumping on the pedal, were you? no, I didn't think so. Have a look at the rear brake and see lf the lever that is on the brake plate has any markings behind it that indicate wear limits. Do you have a manual for the bike? if not, try and get one. If the arm on the rear brakearm is pointing forward, (Item 6) past the vertical by a lot, then it could mean that the brake shoes are worn past their safe limit, what is the adjustment like on the rear brake rod ?(The push rod as you called it, item 7, it is actually a pull rod, or brake rod, but the action is a pull .) if the adjuster nut is screwed a long way down the rod, that would indicate that the shoe are worn. It sounds to me like that could be the problem with the rear brake as for the brake to jam on like that is quite drastic and very dangerous and indicates that the shoes could be jamming on the drum. Another thing to check is the condition of the brake anchor arm, or if you can see the pic. "Brake stopper arm" (Japlish!)(If you can see the attached pic, it is item 1) This should be bolted in about the position you can see in the pic. and should be bolted to the frame or swing arm obout a foot or 18" forward of the brake. Make sure it is secured properly. After reading your post, I think you should definitely have a more detailed look at the brakes. Good luck. FOG.
Many newsgroups, including this one are non-binary. Posts with embedded graphics, etc will be tossed on the floor by newsserver software. Host it somewhere and post the URL. Cheers Goaty -- _--_|\ John Lamp - in beautiful downtown Highton / \ IRC: DoD#:1906 Ulysses#:10185 Vulcan Nomad \_.--._/ http://www.gorider.cjb.net/ Phone: 0409 512 254 v mailto: Fax: 03 5227 2151 Hear no Evo, See no Evo, Fear no Evo
