I have a problem that’s new to me.
New master cylinder.
New HEL lines.
Original Grimeca callipers.
The new master cylinder worked with the old lines, as did the callipers.
I pumped fluid through, topping up the m/cyl as I went, until fluid came out at the nipple end. Then I tried to bleed the system.
Now, I can’t get even the slightest pressure on the lever with the new lines.
Confused, I cracked the banjos at the callipers and fluid oozed out, so if fluid is there, why will virtually no fluid flow through the hose from calliper to jar? I’m using the usual method of hose on nipple with the other end in fluid in a jar. Squeeze lever, open nipple, close nipple, release lever - repeat.
Over the years I’ve had reasonable success in brake bleeding and this is the first time I’ve got absolutely no brakes at all.
The only unusual thing I noticed is the nipples seem to need to be turned out more than usual for fluid to come out.
Is it possible that the fluid at the calliper is just a residue that remained in the callipers, that in fact the hoses haven’t been bled fully, and if so, why?
Obviously something fundamentally obvious is at play here, if only I could see it!
Any ideas? Cheers.
Brake bleed.
Re: Brake bleed.
Not unknown for such problematic hydraulics.
1) pull lever in , tie it in position , tap the brake lines a bit then check next morning.Also check for evidence of leaks.
2) put tube on nipple and force fluid in with e.g. a syringe or try using the syringe to suck the fluid through. This may elicit tiny bubbles which can occur if air leaks past the bleed nipples in which case a thin turn of PTFE tape will seal the threads.Again tap the tubes as you go.
3) guess you tried angling the handlebar to allow air to reach the highest point.
4) small particulates in the master cylinder causing blockages.
It is good practice to have water at hand and a cover over the tank in case of spillages.
If you speak to anyone with the misfortune to have BMW Airhead with rear disc you would not be surprised to find incidents of hydraulic brakes being a swine.
Let us know if you crack the problem.
John
1) pull lever in , tie it in position , tap the brake lines a bit then check next morning.Also check for evidence of leaks.
2) put tube on nipple and force fluid in with e.g. a syringe or try using the syringe to suck the fluid through. This may elicit tiny bubbles which can occur if air leaks past the bleed nipples in which case a thin turn of PTFE tape will seal the threads.Again tap the tubes as you go.
3) guess you tried angling the handlebar to allow air to reach the highest point.
4) small particulates in the master cylinder causing blockages.
It is good practice to have water at hand and a cover over the tank in case of spillages.
If you speak to anyone with the misfortune to have BMW Airhead with rear disc you would not be surprised to find incidents of hydraulic brakes being a swine.
Let us know if you crack the problem.
John
Re: Brake bleed.
Cheers John.
I’ll keep buggering on and give your ideas a try.
I’ll keep buggering on and give your ideas a try.
Re: Brake bleed.
Not a Morini but I've had the same problem with new hoses. Trouble is that air rises so unless you can get that air bubble pushed down it'll always be in the way.
Things I've done in the past:
Lift caliper high and leave overnight, then bleed.
Lift caliper and bleed in that position (!).
Suck fluid through from bottom with syringe.
Use a pressure bleeder at the top to force everything through.
Just keep pumping fluid through for ages before starting to bleed.
Undo the lever and leave that overnight with cylinder at the top (sometimes the handlebar angle means that the highest point is not at the output from the master).
Several of these are as already suggested but just goes to show that you have to try all sorts of wheezes to get there!
Things I've done in the past:
Lift caliper high and leave overnight, then bleed.
Lift caliper and bleed in that position (!).
Suck fluid through from bottom with syringe.
Use a pressure bleeder at the top to force everything through.
Just keep pumping fluid through for ages before starting to bleed.
Undo the lever and leave that overnight with cylinder at the top (sometimes the handlebar angle means that the highest point is not at the output from the master).
Several of these are as already suggested but just goes to show that you have to try all sorts of wheezes to get there!
Re: Brake bleed.
For a stubborn bleeder ( 
) I use the 'lever tied back to the handlebar' technique and leave overnight.
) I use the 'lever tied back to the handlebar' technique and leave overnight.Re: Brake bleed.
The brake lever taped up overnight got me some brakes so I could at least go out for a test ride, I’ll now be using some of the other advice here to try to improve.
Thanks.
Thanks.