brake line problems

[Dave_EH]

Over the past year or so I have rebuilt my brake system.  This includes new master cylinder and booster and lines to and from the m.c./booster.

Today I tried to bleed the system as I need to move my car.

The system won't bleed.  If I take the line off the m.c. I can pump fluid out of the reservoir, although not as quickly as I would have anticipated.

When I put the new line back on and disconnect it at the remote booster end, nothing comes out at all.

With the lines taken off the master cylinder it drips slowly and takes about 2 hours to empty the reservoir.

I used a tube bender to bend the short line from m.c. to booster and I can blow air through it so it is not blocked.

Whats going wrong :'(?

Cheers
Dave

[FB_MAD]

    From your description of the problem it sounds like it's in the M/cylinder somewhere.Has the car been sitting around for a while unused???.Corrosion can take place inside the cylinder as brake fluid is hydroscopic (absorbs moisture from the air)and it doesn't take long for corrosion and muck to build up and start to cause probs like a blockage or similar especially if it's been sitting around for a while.I'd take the cylinder off and give it an internal inspection and clean including the reservoir.Check for a blockage in the main port and compensating port which are the holes in the cylinder body inside the  base of the reservoir.Maybe you might discover a blockage causing the problem.Give it a good blow out with an air blower if you have one.
    It could be something else but I'd nearly bet me left one the prob is in the cylinder somewhere by your description.Hope this info helps.What do others think???Terry.  P.S. If you have previously disassembled the cylinder have a look at the assembly of it.Maybe some part has been assembled wrong.Check with a workshop manual.Also sometimes the M/cylinder can have some initial prime problems with start up bleeds so maybe some attention and perseverance is needed there.They can be cows of things at times!!!

[Dave_EH]

Yeah, I was thinking master cylinder as well.  I bought it fully reconditioned about a year ago and it has been fitted to the car for a few months with no fluid in it.

It seems crazy that the new item would be corroded, as the old was was working fine and had been sitting full of fluid for 5 years.

I guess I could try the old one and go from there.

When I realse the pedal a slight slurping sound can be heard but nothing happens.

regards
Dave

[Al]

Dave,
          Did you bleed the m/c before you put it on the car? If not you won't get any pressure out of it because it is full of air.

   Cheers Al

[Dave_EH]

Al,
No I didn't :P.  Hopefully that will be the problem then :)

How do you bleed the master cylinder?

Cheers
Dave

[mcl1959]

Dave, sounds to me more likely the booster is the problem.  The master cylinder is bled OK if it will drip fluid when the pipe is disconnected, likewise appears to be OK internally if it will push fluid out when you press the pedal.
I assume we are talking about a stock m/c here and a VH40 booster?

With the booster, have you got the input line from the m/c into the port closest to the vaccuum tank. the output to the brakes from the very end of the booster and the bleeder nipple in between the two pipes and pointing upwards, not downwards?
It is possible for the booster to get dry inside and not work correctly.

Ken

[Dave_EH]

Ken,
Yes I have a stock m/c (disk brake type) and a vh40 booster.  It is installed as you described.

Both the booster and the m/c have been sitting around for about 1 year, however have both been totally reconditioned - much like theyw would on a shelf in a shop.

If I disconnect the input to the booster and pump the pedal I still don't get any fluid through the line.  This would indicate a pinched line, yet I can blow air easiliy through the line.

Dave

[ACE]

Hi Dave,
Have you checked that you have freeplay between the brake master cylinder piston and the brake pedal pushrod.
Adjust the master cylinder pushrod to obtain 1/8 inch free movement at the pedal.
Regards ACE  8)

[Al]

Dave,
           Put the m/c in the vice, fill the resevor up with brake fliud, put a container under the outlet port, grab a screwdriver or a long rod of some sort, then pretend that your hand is the brake pedal, push the piston all the way in slowly then release the rod slowly  BUT !!!!before you release the rod put your finger from your other hand ,cover over the outlet port, just repeat that process until you get an even flow of fliud from the cyl. It's a bit messy but thats the way to do it. Also Dave be carefull when you push the piston in fliud will spray all over the place.  Good luck Dave, you'll be right.

     Cheers Al

[Dave_EH]

Thanks Al I will give it a try.

Ace - Thanks, The free play was set correctly.

Hopefully I will have good news soon!

Regards
Dave

[Dave_EH]

After bleeding the master cylinder, it seems that the pipe connection between the master and booster is leaking.

Should there be a washer or something similar in this connection? Fluid/air seems to be able to get bewteen the pipe itself the threaded nut that holds the pipe to the master.

If so, will this be the case at all new connections? T-piece etc?

Regards
Dave

[nicko]

there should be a little copper  washer in between master cylinder and threaded adaptor for pipe fitting

[Dave_EH]

I've got the washer in between the adaptor and the pipe fitting.

It seems to be leaking in between the adaptor fitting and the pipe.

Both are new.

Any ideas?

[Jockster]

Dave
Check inside the adaptor and see if it has a raised tapered seat that will mate with the taper on the brake pipe, if it hasn't you may need to get an adaptor that does have this type seat
Cheers
Jock

[mcl1959]

There are 2 types of pipe seat flares,  one is a ball flare and the other is a reverse flare - all early Holdens use reverse flare fittings but a lot of boosters use ball flare fittings.
As Jockster has said - check the flare types on the pipe as the 2 types are not compatible.

Ken

[Dave_EH]

Ken,

I think that may be the problem.

I'll check it out and go from there.

Should I expect to have a similar problem at the original T piece if this is the case?

Appreciate the help.

Regards
Dave