Can anyone offer suggestions please?
I have rebuilt a 1991 K100RS4v (with ABS) from various boxes of bits where the previous owner had discovered the fun of using a spanner!. I replaced all the front brake hoses with stainless (all the front calipers were in one of the boxes anyway!) and found that, once I had bled the brakes, applying them would cause them to lock on making the bike impossible to move until I released the pressure by slackening off the ABS unit bleed nipple. I assumed that the old pistons were sticking in the calipers so ripped them all out and replaced all the seals and pistons with new but still have the same problem. The handlebar lever is rock solid but then, it would be since there is nowhere to move the pad to! If I release the pressure using the ABS Unit bleed nipple and leave it open overnight the pads move away from the disks and the wheel rotates freely (but I am slowly stripping all the paint off the ABS unit!). It seems as though the fluid can't return through the system when the lever is released. There appears to be no fault showing on the ABS Controller and the ABS lights go out when the bike is rolling (until I apply the front brake then the bike becomes immovable again!). Any ideas? 
-
-
We recommend to use new brake hoses, and doing so, take the modern steel-flex (?) if possible. With the age of the hoses, their diameters are reduced - accelerated by n ot using them, on stock with air contact or very old brake fluid...
Also the lever has to have some space to release the pressure in the system. On the 4V i guess is it adjustable...
-
could be a bit stupid, but, I had the same problem, but, with no ABS, a so called mechanic had put to much brake fluid in the resovervoir....
-
An interesting idea, I thought the rubber bellows in the master cylinder was supposed to provide the space without allowing air to be in the fluid reservoir, I'll try taking a bit of fluid out and see what happens.
For Hoechst - all the lines, except the rigid steel ones, have been replaced with new stainless braided hoses. I reasoned that the rigid steel pipes would not need replacement.
-
Solved!
There is a tiny hole - perhaps 0.05mm - in the fluid reservoir which was blocked! I didn't even know it was there, it is THAT tiny. Thank you to Tim at James Sherlock's (DevonBMW) for the hint - that man is a genius
-
Zitat von "Solong"
Solved!
There is a tiny hole - perhaps 0.05mm - in the fluid reservoir which was blocked! I didn't even know it was there, it is THAT tiny. Thank you to Tim at James Sherlock's (DevonBMW) for the hint - that man is a genius
Yep, the return orifice. When calipers won't return after releasing the brakes it's the first place I look. They get cruddy over time.
ABS adds an additional layer of complexity to ponder.
Jetzt mitmachen!
Sie haben noch kein Benutzerkonto auf unserer Seite? Registrieren Sie sich kostenlos und nehmen Sie an unserer Community teil!