QuestionTaking delivery of a vintage suzuki 450 1980
The front brake does not work.
The owner says fluid pumps through when he bleeds the brake but does not produce pressure.
Screw is missing on the top fluid reservour. He said he thinks that could be the problem as it can't produce a vacume (? vacume in brakes?)
It sounds to me like a master or caliper rebuild.
I'm new at motorcycle repair, hence the dumb question.
AnswerHi Jim,
It's likely a caliper rebuild. Brake fluid reservoir is vented to atmosphere, so no vacuum there.
Brake fluid changes chemically with time and when exposed to air/humidity. This change is most commonly noticable in the calipers, behind the piston seals. You may need to fabricate a "special tool" to clean the seal grooves. One guy usses a pop-sicle stick cut to size. I use a allen wrench with ends angled at 45 & 90 degrees. I ground flat screwdriver like tips to the tool to aid scraping grooves (after determining a comfy grip and which sides to grind).
Remove caliper, drain fluid from caliper, chase with brake spray cleaner, carefully remove pistons with compressed air, you can also remove pistons by carefully rotating & pulling pistons with pliers by gripping piston edges (where they contact pads), remove seals and clean.
Send me an email address and I'll return repair files.
Respectfully,
Mark Shively
