Brake servo engine stall - HELP

[fredamens]

I previously had an issue with my braking, in short I had to put a lot of pressure on the brakes to get it to stop. Had it looked at and it turned out to be the servo. After a nightmare finding one that fit - the servo for a 71 is slighter smaller (10mmish) believe it or not I ended up buying 3 used ones and none fitted before I realised. Thats another story. All was well and then I fitted twin carbs.

When I brake it now it doesn't feel like the servo is working and it also slows down the engine, taking air, and eventually it stalls. I have checked all the lines and cannot see any issues so could it be the servo gone again?

Reading up someone said it could be an in-return valve. Like this one.

Anyone had this issue and can shed some light on the problem it would be really be appreciated.

Thank you all in advance.

Fred




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[ozziedog]

Does sound like you ain`t got your servo working properly, first thing I`d check never having a servo that is, is if there is any leaks. Non return does sound plausible.

Ozziedog,,,,,,,,,,,,,,Brakes on a van,,,whatever next. :mrgreen: :lol: :mrgreen:

 

[fredamens]

That's what I thought. Do you think that sort of thing can cause the stalling? My thanks


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[gvee]

Yep.
Big enough change in air-fuel mixture can cause stalling.

 

[fredamens]

Thats. Makes sense to try this first before going all in with a servo.


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[gvee]

You could always block the servo pipes at the engine end and see if you see the same symptoms?
Would help prove it is related to something in that part of the set-up.

 

[subheatadey]

Is your non return valve operating as it should and is it facing the right way?

 

[Jim Bob]

Had the same problem with mine, replaced the pipe from the servo to the engine bay and this solved the stalling issue

 

[fredamens]

Those are both great points. I will check the weekend and see. Thank you


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[fredamens]

Just getting around to this. Can anyone point me to the location on the non-return valve, where is it located? I have had a good look around the engine bay and cannot find it. Many thanks


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[StuF]

There will be a takeoff for the vaccum from the carbs - follow that vac line under the bus and it will be between the servo and takeoff somewhere, mine is around the gearbox area for access should I ever need to replace it

 

[fredamens]

That’s much appreciated. I will take a look.


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