More vfr problems

[andym]

First off a quick update on my previous issues:
The running issues was down to a kink in the fuel line, 2 new 90 degree connectors and new fuel line connectors and no more running issues.

The electrical issue was down to the rear brake plug had been sitting on the exhaust and melted through causing it to short (which would explain why it was more obvious at higher revs).

Those problems have been sorted and I took it for an MOT the other day and it failed on a loose rear light (fixed with cable ties) and the front brakes binding (which is where the problem is now).

Because I didn't have the correct tools I had to try cleaning them up as best I could, but when I took it back the guy lifted the front end and spun the wheel, then pressed the brake and tried again (at least I know how to test it now )

So I borrowed some tools and bought some cleaner and set about trying to sort them.... but I'm still having issues.

So far I've stripped the calipers down 3 times, the pistons are gleaming, the seals look fine (there was a bit of crud that I've cleaned off), when I push the pistons back in they more or less fall straight into place with very little pressure. Now everything is as clean as I can get it, but the front wheel still feels stiff to move, and since the calipers have been stripped the brakes lose pressure after about an hour, but there is no fluid leaking out that I can see.

I did notice that the pads on 1 side are almost down to the wear markers, but not sure if that would be causing a binding issue, also would cleaning the seals (with a cloth and brake fluid) have caused them to be causing a slow leak?

I know at some point I'll need to replace the pads and seals, but since I've come up to Glasgow I've had nothing but bad luck....

Tl;dr: stripped calipers 3 times and still fucked

[Hetzer]

You most likely have air still trapped in the lines and/or calipers.
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"There's the horizon! Ride hard, ride fast and cut down all who stand in your way!"

[andym]

[Howling TerrorOutOfOffice]

I'd expect some resistance when pushing the piston back in, then a satisfying clunk as it hits home.

Had a similar problem with a piston that wouldn't return (stay put). Removed the seals and cleaned the groove out with a whittled matchstick and blasts of brake cleaner. New seals are inexpensive and some of that red rubber grease.

Job jobbed.
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[Hetzer]

I had to use a sharp piece of metal scraper to get the oxidised crud out of the grooves in mine. Not so sharp as to score the metal though.
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"There's the horizon! Ride hard, ride fast and cut down all who stand in your way!"

[mr jamez]

They're sliding calipers, so its common to have problems with the pins getting corroded and getting stuck in the rubber seals. Ideally they should slide nice and freely. If they are very difficult to pull apart then replace the pins and rubbers.
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[prawny1]

Are your levers original, and did you clean the master cylinder at the same time?

When bleeding twin caliper systems I use a hose clamp to block off one of the calipers so that I can bleed them individually.

Once I get good lever feel on one I clamp that hose and release the other so that I can bleed it.

If you leave them both open you are compressing the air in the other caliper all the time so may take ages to clear it all.

Another thing to check would be whether you have all the pads, clips and shims in the right place, and if your calipers had been binding for a while check whether the discs are bowed from the heat and pressure.
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[andym]