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power aassistance required
Posted: Thu Aug 04, 2022 9:42 am
by maggieminor
Hi everyone, my minor has standard drum rears and marina front discs with the remote fluid top-up bottle. I have tried fitting two types of remote servo units, but in each case, vacuum is held by the servo but there is absolutely no effect to the braking effort. There is no air in the system, adjustment all good (no "pumping up" of pedal travel), - the brakes work the same as if no servo fitted. Has anyone come across this problem? - and if so, is there a way of fixing it?
Re: power aassistance required
Posted: Thu Aug 04, 2022 10:05 am
by Sleeper
Sounds like the servos weren't working , were they Lockheed , Girling or Powertune ?
Photo?
Easy to plumb in the input and output pipes the wrong way..
John ;-)
Re: power aassistance required
Posted: Thu Aug 04, 2022 7:48 pm
by maggieminor
Thanks for your reply Sleeper. I have had the units apart and have checked the operation of the air ccontrol valves. All ok. It seems as if the piston in the servo (although free moving) does not move far enough to actuate the air control valve? Any further ideas?
Re: power aassistance required
Posted: Thu Aug 04, 2022 9:15 pm
by simmitc
Leak in the vacuum connection? The kits usually recommend a non return valve, but do not supply 1
However, they are available separately.
Re: power aassistance required
Posted: Thu Aug 04, 2022 10:17 pm
by maggieminor
Hi everyone, thank you for your replies. All of your suggestions have been welcomed, but I have already made such checks and all is well. In my original post, I should have mentioned that with the engine off, I can repeatedly press the brake pedal and lose all vacuum (can hear it) but, keeping my foot on the pedal and then turning on the engine, the pedal does not sink, as, apparently it should. Could this be a clue?
Also, if anyone could explain why, mechanically, the pedal should sink in this manner, it may help me understand where a fault may lie.
Re: power aassistance required
Posted: Fri Aug 05, 2022 7:43 am
by daveejhitchins
maggieminor wrote: ↑Thu Aug 04, 2022 10:17 pm
Hi everyone, thank you for your replies. All of your suggestions have been welcomed, but I have already made such checks and all is well. In my original post, I should have mentioned that with the engine off, I can repeatedly press the brake pedal and lose all vacuum (can hear it) but, keeping my foot on the pedal and then turning on the engine, the pedal does not sink, as, apparently it should. Could this be a clue?
Also, if anyone could explain why, mechanically, the pedal should sink in this manner, it may help me understand where a fault may lie.
I was asking the same questions myself, the other day, as I'm in the process of replacing every part of my Travellers system.
I found some good explanations of how servos work on YouTube - search "How do brake servos work" on YouTube. There's quite a few to look at.
I doesn't matter if they don'e explain your exact system as the basics are the same.
Edit: The 'need' for a one way valve is also explained . . .
Dave H.