Brake Bleeding

[johnm]

I replaced the drums all round, all linings and all front cylinders, but not rear cylinders yesterday.

I spent some considerable time bleeding the fron brakes until there was no sign of air. I was careful to keep the master cylinder topped up.

The brakes were then left to settle ovenight but still don't come up firm first time. It takes a couple of pumps to get a "good pedal"

Do I assume that I've still got air in there and keep bleeding a little longer and/or should I have a go a bleeding the rears too even though I didn't do anything to them?

[8009STEVE]

I normally start at the nearest to the master, work to the furthest, then back to the nearest.

[Matt]

You need to bleed the rears too... air could have got to the rears.

I think your meant to start bleeding at the furthest point to the M/C and move closer

[johnm]

Thanks chaps, I'll give it another go this afternoon.

[Packedup]

Have you made sure they're adjusted up properly?

A couple of pumps from poor to solid could mean poor adjustment. And agree with havign to bleed the rears - If you clamped off the flexis when doing the fronts then that shouldn't really be necessary (but doesn't hurt), but air might have got in otherwise.

[jonathon]

Make sure that the brakes are adjusted fully off. Release the handbrake and then bleed n/s/r,o/s.r/,n/s/f, o/s/f. Only when fully bled do you re adjust the shoes. A falling pedal is either air or a seal gone, the latter not uncommon when bleeding brakes as you use the full travel of the pedal.

[bmcecosse]

I never clamp off flexis - whatever you use (even the special tool sold for the job) it damages the tube - and next thing it's ballooning up and fit to burst!! Yes try bleeding the rears - and always start at far point from master cylinder.

[johnm]

OK. I've had another go and I've read Jonathan and bmcecosse posts so thanks to all for advice.

I've bled with shoes adjusted up and handbrake off. The pedal takes three pumps to go solid after it's "rested" from the bleeding operations and still takes the same three pumps half an hour later.

After the the third pump it's solid so I don't think seals can be the issue, I assume therefore I just need to keep at it, though there's no longer any obvious sign of air in the brake fluid coming out.

That said it is pretty dirty from the rears and the near side rear nipple was badly corroded and I had to take it out and clear it, so I'm sure that a complete flush wouldn't hurt, so unless there's further advice I'll just keep plugging away I won't get another shot at it until next weekend now though.

[8009STEVE]

I know this sounds silly. Have you adjusted both shoes on each front wheel? Just a thought.

[Packedup]

I know this sounds silly. Have you adjusted both shoes on each front wheel? Just a thought.

That's what I said

Bleeding might be done with everything backed off, but out of adjustment brakes are out of adjustment brakes - And out of adjustment brakes may well need a couple of pumps to get the pedal where it should be.

I'd be adjusting the brakes at this point...

Agree on master cylinder failure after bleeding, had it myself on a few cars, but in my experience it's more a pedal that won't stay solid than a couple of pumps to get solid.

As for clamping hoses, I don't like doing it, and the purpose made clamp seems if anything too narrow compared to protected molegrips, but it's one way of making sure you don't have to bleed the whole system. Better but slightly messier IMO is to put a bit of cling film over the filler hole - No air in means no fluid out, though in practice there's always a bit of leakage that way, but nothing major

Then again, with the Minor master being buried in the depths of the chassis, is there much of an opportunity for fluid to fall out? It can't be far off beign lower than the end of the flexi when you've got the front brakes in bits...