My front brakes on my 1990 vfr 750 have been sticking ever since I changed the pads. I am preety sure that I put them back together correctly, but since then the piston in the calipers dont appear to be returning correctly as they appear to be staying on. I hadnt changed the brake fluid for a year and a bit so I thought that I would change that to see if it helped but it doesnt seem to have. Due to its age (70 000 kms which is about 45000 mi) I thought that it might be the calipers sticking but it is strange that it has only happened since I changed the pads. Any suggestions? I wanted to know what people think before I go and take it apart again. Thanks in advance to all who reply.
2007-02-18 22:21:16 · 6 answers · asked by vertical c 2 in Cars & Transportation ➔ Motorcycles
There is a small check valve, usually a ball bearing inside a passage in your master cylinder. This allows pressure to close the pads when the lever is squeezed but also allows brake fluid to return back into the reservoir when the lever is released. These tend to get stuck, especially on older bikes causing the brakes to lock up.
Using a very small piece of wire or paperclip, remove your reservoir cover and look for the hole. Gently probe the wire in there to free the check valve and then do a complete brake bleeding to check for proper operation.
You'll know this is working by SLOWLY squeezing the brake lever with the cover removed and releasing it. If the check valve is working, you will see the fluid squirt up out of the hole. When doing this, keep the reservoir level and make sure you don't spill any or get it in your eyes. Only use new brake fluid from an unopened container and make sure it's the recommended type (i.e.: DOT-3, DOT-4, etc...) Mixing various types of brake fluid is a big no no as some are glycol based and others are silicone based.
Also check the caliper pistons for corrosion. You can eliminate any surface corrosion by using steel wool or Scotchbrite. Don't overdo it and don't damage your rubber seals in the process. Follow this up by wiping them down with a rag wetted with mineral spirits. Make sure no solvents or oil get on your brake pads.
Good luck...
2007-02-19 01:54:59 · answer #1 · answered by Anonymous · 0⤊ 2⤋
Because the old pads didn't have much meat left on them the pistons will have been sticking out quite far. This allows road crud to build up on them. Then when you fitted the new pads the pistons were pushed much deeper into the caliper and now that build up of crud will be getting stuck on the dust seal.
No need to totally dismantle them. Just remove the pads, stick a piece of wood in the caliper to stop the pistons coming out all the way, and pump the pistons out until the dirty section is exposed. Then use some brake cleaner (specifically brake cleaner, not degreaser or anything else like that) and a toothbrush to clean them up. Reinstall the pads using a smear of copper grease on the back of the the pads and it should be fine.
2007-02-18 23:09:16 · answer #2 · answered by SpannerMonkey 4 · 4⤊ 1⤋
in line with what you have defined, i'd use the old caliper for a doorstop and get carry of a extraordinary rebuilt caliper or a robust used one. in spite of everything, the nicest looking bike isn't worth to a lot if it won't provide up. And once you communicate approximately that the bike has in basic terms been ridden sporadically considering 1994, the rust buildup interior that caliper will, ought to you get the piston freed up, tear up the piston seal and be a continuing source of leaks. And mutually as you're at it, i'd look at or have a qualified bike mechanic look at the grasp cylinder and rubber brake hose. The hose would look superb from the outdoors, yet hoses will swell up internally from loss of use or appropriate maintenance (prevalent fluid transformations) and which will ward off the brakes from working extraordinary. Brake fluid, enormously DOT 3 spec'd fluid, has an inclination to soak up moisture. better than possibly the fluid hasn't been replaced in 2 many years. it is your neck, so it relatively is one section i does not do one million/2 way.
2016-10-16 00:08:32 · answer #3 · answered by ? 4 · 0⤊ 0⤋
remove caliper and diassymble clean it good reassymble use fluid to lube it reinstall bleed system and try it if not get a new caliper and brake line the rubber in the line could be colapsing also check that too
2007-02-18 22:31:09 · answer #4 · answered by Anonymous · 0⤊ 2⤋
Could be the brake fluid resevoir is to full.
2007-02-19 03:59:09 · answer #5 · answered by (A) 7 · 1⤊ 2⤋
this is probably a brake lining (hose) that is partially collapsed inside...you won't be able to tell it by looking at the hose!
2007-02-19 03:23:36 · answer #6 · answered by Robert P 6 · 0⤊ 4⤋