ausmini :: View topic - Desperate for advice on sorting out brakes on 77 resto

Hi all

We've been trying to get the brakes sorted on my 77 Leyland mini resto but with no success so far. :cry:

As its a 77 model it has the later tandem type Master Cylinder which, by all ausmini accounts, is a bit of a bugger. Advice is much needed.

The problem is that we can't get any pressure at the pedal.
So far we have :
Rebuilt MC with new internals and is working ok.
We get fluid when we crack the nipples.
We don't think there is any air left in system (used a vacuum pump)
New wheel cylinders, springs, shoes.
Handbrake cleaned up and adjusted.

Have tried Matt's method (release all nipples and let them drip feed).

Could it be the pressure regulator/bias valve (not sure of exact name)?

Thanks for any help.

Eiles

Author:	shnitzee [ Mon Aug 01, 2016 12:48 pm ]
Post subject:	Desperate for advice on sorting out brakes on 77 resto
Hi all We've been trying to get the brakes sorted on my 77 Leyland mini resto but with no success so far. As its a 77 model it has the later tandem type Master Cylinder which, by all ausmini accounts, is a bit of a bugger. Advice is much needed. The problem is that we can't get any pressure at the pedal. So far we have : Rebuilt MC with new internals and is working ok. We get fluid when we crack the nipples. We don't think there is any air left in system (used a vacuum pump) New wheel cylinders, springs, shoes. Handbrake cleaned up and adjusted. Have tried Matt's method (release all nipples and let them drip feed). Could it be the pressure regulator/bias valve (not sure of exact name)? Thanks for any help. Eiles

Author:	MiniBrad [ Mon Aug 01, 2016 7:25 pm ]
Post subject:	Re: Desperate for advice on sorting out brakes on 77 resto
One of the guys at work had a very similar issue to this & I think it his something to do with the wheel cylinders themselves not being completely true & leaving a small air pocket that was near impossible to bleed out. He is currently in the US at the moment so I can't clarify what he did to fix them but he ended up correcting his. Are you just having a very low pedal or spongy pedal? Brad

Author:	DavidE [ Mon Aug 01, 2016 7:28 pm ]
Post subject:	Re: Desperate for advice on sorting out brakes on 77 resto
shnitzee wrote: Hi all We've been trying to get the brakes sorted on my 77 Leyland mini resto but with no success so far. As its a 77 model it has the later tandem type Master Cylinder which, by all ausmini accounts, is a bit of a bugger. Advice is much needed. The problem is that we can't get any pressure at the pedal. So far we have : Rebuilt MC with new internals and is working ok. We get fluid when we crack the nipples. We don't think there is any air left in system (used a vacuum pump) New wheel cylinders, springs, shoes. Handbrake cleaned up and adjusted. Have tried Matt's method (release all nipples and let them drip feed). Could it be the pressure regulator/bias valve (not sure of exact name)? Thanks for any help. Eiles Have you adjusted the shoes?

Author:	shnitzee [ Mon Aug 01, 2016 8:05 pm ]
Post subject:	Re: Desperate for advice on sorting out brakes on 77 resto
Thanks Brad, will double check wheel cylinders. Very low pedal. DavidE - have adjusted shoes.

Author:	justfanginaround [ Mon Aug 01, 2016 8:06 pm ]
Post subject:	Re: Desperate for advice on sorting out brakes on 77 resto
I just wen't through this with my 77. adjust rears till they are tight but turn, make sure handbrake is off lol we bled the front left first, then right front, rear left, rear right making sure there is always a good supply of fresh fluid in the master. on night 1 we had a softish pedal ......we drank scotch. returned for night 2 to find .... no pedal !! Re bleed ....lhf, rhf, lhr, rhr and omg we have a fantastic pedal. We figure that the trapped air in the sys settled overnight and was then easier to get out. Dont stress and let Johhny, Jimmy or his mate Jack help

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Author:	shnitzee [ Mon Aug 01, 2016 8:14 pm ]
Post subject:	Re: Desperate for advice on sorting out brakes on 77 resto
Thank you! Will give it a go. Cheers Eiles

Author:	Stev0 [ Mon Aug 01, 2016 9:13 pm ]
Post subject:	Re: Desperate for advice on sorting out brakes on 77 resto
If you've got real problems what I have been led to believe is that pressure bleeding the brakes will do the trick, but of course you need to pay for this to be done. I've had similar problems myself.

Author:	Lillee [ Mon Aug 01, 2016 9:38 pm ]
Post subject:	Re: Desperate for advice on sorting out brakes on 77 resto
Side note: Not sure what type of vaccum bleeder you have but by undoing the bleed nipple, air can be sucked back in via the screw thread itself if you undo it too loose when bleeding. I can't use a vacuum bleeder for my rear brakes for this reason, only good old step on pedal method works 100% for me. (But it could just be my amaturish skills )

Author:	gtogreen1969 [ Mon Aug 01, 2016 10:06 pm ]
Post subject:	Re: Desperate for advice on sorting out brakes on 77 resto
I always have the brakes backed off so the pistons are all the way in before starting a bleed. With the pistons all the way in there are less places for air to hide. I start with the gravity feed to prime the lines and finish off with a vacuum bleeder. I also have a one-man bleeder kit or use a second person to do the pump, hold, crack nipple thingy if the car is not responding. I have noticed on the Leyland minis that if you push the brake pedal too hard when a nipple is cracked then the brake pressure regulator valve will cause you issues. If you pump gently then no worries. Then re-adjust the shoes and test.

Author:	simon k [ Mon Aug 01, 2016 10:17 pm ]
Post subject:	Re: Desperate for advice on sorting out brakes on 77 resto
are your flexible brake lines old and crappy ? I know a guy who got a new tandem MC and it was no good out of the box... couldn't get a pedal otherwise the few times I've helped people sort out brakes that just won't bleed I've done it by a process of elimination, put a bleeder in the outlets of the master cylinder, make sure it's rock solid. Put one of the lines back in and check/bleed that circuit, if you can't get a pedal there, then clamp each of the lines with vice grips to isolate each wheel, find the culprit.... eliminate

Author:	gtogreen1969 [ Mon Aug 01, 2016 10:33 pm ]
Post subject:	Re: Desperate for advice on sorting out brakes on 77 resto
shnitzee wrote: Could it be the pressure regulator/bias valve (not sure of exact name)? Eiles http://www.minimania.com/BRAKES___Rear_ ... adjustment "The FAM7821 regulator valves are a pain. Impossible to tell if they're working properly, cause all kinds of grief when trying to bleed the complete system should the wrong method be used, and are not re-buildable. If it fails - you have to buy a new one."

Author:	Stev0 [ Mon Aug 01, 2016 10:45 pm ]
Post subject:	Re: Desperate for advice on sorting out brakes on 77 resto
Lillee wrote: Side note: Not sure what type of vaccum bleeder you have but by undoing the bleed nipple, air can be sucked back in via the screw thread itself if you undo it too loose when bleeding. I can't use a vacuum bleeder for my rear brakes for this reason, only good old step on pedal method works 100% for me. (But it could just be my amaturish skills ) No, pressure bleeding. My understanding is that they pressurise the master cylinder reservoir allowing you to bleed each wheel without needing to pump the pedal which may create many small bubbles which can be hard to bleed out.

Author:	gtogreen1969 [ Mon Aug 01, 2016 11:12 pm ]
Post subject:	Re: Desperate for advice on sorting out brakes on 77 resto
You may need to recheck the Master cylinder. If you can't get a pedal and there is no air left in the system it could be the pistons are not returning all the way. This is what I have done in the past. Get someone to slowly pump the brakes a few times then hold the pedal down and slowly crack a fitting at the MC and then tighten again. Just make sure you have a few rags under the MC and wear eye protection. As the pedal starts to come up the pressure will increase. That is when I wrap the fitting in a rag just in case. Just like bench testing but on the car.

Author:	shnitzee [ Mon Aug 01, 2016 11:50 pm ]
Post subject:	Re: Desperate for advice on sorting out brakes on 77 resto
Thank you for all the replies guys. Lots of good information. Much appreciated. We will try one thing at a time and see how things go. Cheers Eiles.

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Author:	drmini in aust [ Tue Aug 02, 2016 3:03 pm ]
Post subject:	Re: Desperate for advice on sorting out brakes on 77 resto
re the FAM valves, I'm pretty sure John Smidt used to rebuild these. I had a low pedal in Barney with an LS tandem MC when rebuilt, nothing worked, best I got was 1/2 pedal. So I drove to B&R Brakes and gave them $30 to bleed it properly.