Bongo Fury

Dear all,

I like to think myself as being reasonably savvy but I'm a bit stumped so any suggestions....

Basically my front brakes are dragging to the point they are getting hot and smelly so I can't use it. It did appear to be just one caliper at first so I squeezed the pistons almost all the way out, cleaned them up, greased them and the sliders and then it worked alright but now both are sticking on. Is there anything that would stop the pistons retracting apart from sticking pistons?

Any thoughts? Russ

Brake fluid been changed in the last two years? It absorbs moisture which leads to poor hydraulic performance and corrosion within the pipes and calipers.

If needed you're near Allan's.

Simon Jones wrote:Brake fluid been changed in the last two years? It absorbs moisture which leads to poor hydraulic performance and corrosion within the pipes and calipers.

Yea but no but. I finally changed mine this year after 9 years of ownership and I'm pretty certain it hadn't been changed for a few years before that, and I had no problems although possibly the brakes have a little more 'feel' since fluid was changed. I'm not proud about it or anything, and maybe its the exception that proves the rule, but......

The strange thing is that is has happened so suddenly and on both front callipers.

I worked the pistons in and out on one caliper after cleaning the pistons with brake cleaner and then greased them as I have done numerous times before. The brakes are working great but not releasing.

Fluid was changed with abs pump a few years back.

rustyp , check the brake light switch on the pedal bracket has plenty of clearance.

I have found that heavy rust and scale on the caliper needs chipping / scraping / smoothing off so the pads move freely and the slide pins / tubes are polished and lubed ..

I used to use copper grease .. but now use a nickel based anti seize lube ..

I used to use copper grease on my motorbike pistons but I am sure that this caused them to stick. Then used brake red grease as advised and not had problems since.

I never use any type of grease on brake cylinder pistons .. a bit of 'red' on the rubber dust cover that's it ..

teenmal wrote:rustyp , check the brake light switch on the pedal bracket has plenty of clearance.

Also make sure that the MC operating rod has clearance, it could also be the MC is not fully returning and building up a pressure ..

Good Luck

are the stainless pad sliders fitted and cleaned and lubricated if they are, (some are usually missing) have you removed them and cleaned off the casting beneath them, rust and crap can build up beneath them and lift them slightly making it harder for the pads to slide, rubbish garages / fast fit places dont do this. .

http://lushprojects.com/bongopartsmk2/c ... mgno=.html

Had similar problem with sticking piston causing brake bind. Dust boot (caliper end) had been pushed out of locating grove at one small section where there was corrosion to piston. Compressing piston fully almost aligns piston dust boot groove with caliper dust boot groove and was able to remove dust boot without damage, extend piston, clean piston and get to move freely, checking that it retracted when pressure off foot pedal. Bleed nipple corroded and unmovable. Needed to use vehicle while awaiting new caliper but could not replace dust boot. On examination of dust boot there is a thickening of the rubber on the inside of the caliper locating part of the boot, almost like a casting seam. This may be why the boot had been pushed out as the piston corroded. Turning the boot inside out I was then able to very carefully remove this seam on the grinder without affecting the part that located in the caliper. With plenty lub,I was able to work the now thinner section of the boot back into place until it located in its recess through the small gap between the piston and caliper. I had to rig up a rod to hold the piston back fully while this was done otherwise the piston tended to move forward and close the gap. It is only a temp measure in this case but could be useful in the event that you just wanted to replace a damaged dust boot.