servo assisted brake problem

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blackshadow
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servo assisted brake problem

Post by blackshadow »

Can anyone help...? I have recently changed the retro-fitted servo on my 1971 Traveller and also the long brake pipe that goes to the master. The brakes bled up easily to a very healthy pedal but after two days the pedal goes soft and after four or five days it has all but disappeared. When I re-bleed it the air comes out easily. I can't spot any leaks and I have checked the unions at the master and servo. Where is the air coming from!? Thanks.
john newton
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Re: servo assisted brake problem

Post by john newton »

was servo new or s/hand,,,played about with,can you manufacture link pipe to cut out hyd/pipe to servo inorder to prove source of air coming from servo or not.re john newton.
blackshadow
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Re: servo assisted brake problem

Post by blackshadow »

Hi John...many thanks...the servo is new...Ok thanks...good idea will try and eliminate servo first...
firehor5e
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Re: servo assisted brake problem

Post by firehor5e »

Do the unions up tight,check and check again,air can be pulled in,even if fluid is not leaking out,worth having a look at the wheel cylinders too.
1968 2 door 1275
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Re: servo assisted brake problem

Post by Sleeper »

Is it a "Powerline" servo ?

John :wink:
blackshadow
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Re: servo assisted brake problem

Post by blackshadow »

Hi John..thanks for your reply...I think so. It's not one of the expensive ones - it was 80 quid from MGB hive. I have now noticed that there is a tiny fluid weep from the bottom union - despite the pipe being very tight. I'm now thinking of putting the old servo back on to see if it holds pressure. I have a feeling that the budget servos are not well made...
Sleeper
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Re: servo assisted brake problem

Post by Sleeper »

I think the dustbin would be the best place for it,from reports I've heard..

John :wink:
Mark Wilson
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Re: servo assisted brake problem

Post by Mark Wilson »

MGB Hive sell Powertune servos, which is what I assume we are talking about here. David Manners, who are usually very reliable, sell what appears to be the same kit at much the same price. Can anyone tell me if I would be getting anything different if I pay twice as much at ESM - aren't they all made in the "same tin hut in a far away place" (copyright BMCEcosse :) ) And the servo assistance ration varies from 1.6 to 2.3 - the most common is 1.9. What is recommended.

Before anyone takes up Roy's mantle and tells me not to fit a servo, I've dodgy knees and and a wife who's forgotten that she learned to drive in the 1970s. :-?

Mark
Last edited by Mark Wilson on Tue Jun 27, 2017 12:19 pm, edited 1 time in total.
mits
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Re: servo assisted brake problem

Post by mits »

Hi could anyone tell me which outlet I need to use when fitting a remote servo is it the one on the side that goes to the servo or one at the back on the master cyl and do I block the one I don't use,
many thanks,
Tony.
Mark Wilson
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Re: servo assisted brake problem

Post by Mark Wilson »

There's only one outlet from the master cylinder, located at the rear, but it splits to the side and rear by using a banjo fitting. If you are fitting your servo to operate both front and back (which you should) you block off the rear pipe and connect the side outlet pipe to the servo inlet.

Mark
mits
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Re: servo assisted brake problem

Post by mits »

Hi mark at the moment I have 2 outlets on my standard master cyl sitting in the car as you look down at it and 2 on the servo as in pics
the one on the side of the master with the banjo do I get rid of that and make a new pipe to which one on the servo?
thanks.
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Sleeper
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Re: servo assisted brake problem

Post by Sleeper »

You go into the servo at the side ( from master cylinder ) and out to the drums/discs at the nose...

John
mits
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Re: servo assisted brake problem

Post by mits »

nice one thanks john.
mits
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Re: servo assisted brake problem

Post by mits »

Hi another problem ive just encountered is I don't appear to have a vacuum out let anywhere its got a 948 engine in it with looks like cast iron inlet and exhaust manifolds as one fitted wit an su carb, the only place I can see is vacuum pipe going to the dizzy.
any ideas on that please
Sleeper
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Re: servo assisted brake problem

Post by Sleeper »

Spacer between carb and manifold? Drill and tap an outlet...They can be bought..

http://www.ebay.co.uk/itm/SU-HS2-1-Carb ... xyUrZSwqNv

I used an old bicycle inner tube valve fitting and some epoxy resin..

John
mits
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Re: servo assisted brake problem

Post by mits »

that's brill john it looks like theres already one on it ,
thanks again
Tony.
Mark Wilson
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Re: servo assisted brake problem

Post by Mark Wilson »

mits wrote:Hi mark at the moment I have 2 outlets on my standard master cyl sitting in the car as you look down at it and 2 on the servo as in pics
the one on the side of the master with the banjo do I get rid of that and make a new pipe to which one on the servo?
thanks.
As I said, it's one outlet split two ways by the banjo. Blank the rear one and use the side for the pipe to the side of the servo. You can blank the rear with a bleed nipple, but as I was replacing everything I found it neater to replace the rear pipe fitting with a plain banjo bolt. Needs to be the right one, though, with a wider copper washer at the bolt head

http://www.morrisminorspares.com/brakes ... ii-p829432
mits
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Re: servo assisted brake problem

Post by mits »

thanks mark i will get one of those,
tony.
Smithy1961
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Re: servo assisted brake problem

Post by Smithy1961 »

Im fitting a servo but only piping it to the front brakes.Im taking the feed from the brake switch at the front running it thou the servo and back to the switch ,

What ever you should have a one way valve in the vacuum hose.

If I ever changed it to all around servo I think I would have a bias adjuster in the system to regulate front to back.
mits
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Re: servo assisted brake problem

Post by mits »

ok servo fitted to car now need to pipe it all up here is a pic of my master cyl is that all ok or do i need to alter anything (like the bleed nipple which is acting as a blocker)
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