The servo itself has nothing to do with the fluid, it merely assists the master cylinder. If you're having sporadic braking issues, you'd need to be looking at the master seals.
I had an odd issue with my old talbot samba where the seals had worn in such a way that they'd push fluid to both circuits, then one, then the other causing very odd self-steering brakes.
How old are the flexible brake hoses as these often cause problems on classic cars as they collapse internally? Also what angle does the master cylinder sit at; is the back end higher than the front? The master cylinder on Jensens used to be higher at the back end and trap air, to bleed the brakes properly you used to have to jack the car up at the back end to raise the front of the master cylinder which would allow the trapped air to be bled out of the system. To test the servo; hold the brake pedal down hard without the engine running, you should have a solid pedal, start the engine and the after a couple of seconds you should feel the pedal go down more as the servo assist kicks in, if it doesn't go down more your servo isn't working.
The master cylinder is horizontal in a Moggie, good call about the flex is though.
But air is getting in Tim said, I'm wondering if a union needs tightening, or if the end was flared ok. Who did the fitting and pipe work for the servo Tim?
Another thought, and I've not experienced it or heard of it, but the master cylinder from memory is cast, so there is always a chance you have a porous casting, even though it has been refurbished.
Another thing worth doing if you can be bothered Tim is to have a header tank on the brake master cylinder mounted in the engine bay. It means you don't have to keep lifting the carpet and checking in the footwell for brake fluid level.
Great cars though, so much fun with 45bhp and 145 section tyres, four wheel drifting ftw!
On to Pigeon, I started her up again today, she started on the button, not a cough in sight. Furthermore, if she did have compression problems, wouldn't she blow white smoke from cold and if anything, get better as she warmed up? It seems the amount and colour of smoke is variable and the only variable is the amount of air entering the pump. Soon after start up, there was no sign of air. A mate of mine reckoned she looked fine for emissions, so I had him do the mot style rev test while I looked and I'm inclined to agree. So I've taken the big broad decision to enter for mot, as is, with the exception of curing the power steering issue.
So she's sorned for this month but if I can get the power steering sorted in the next week (gonna piss down tomorrow) then I'll mot and tax her for October. She's looking smart and sounds full,of xud awesomeness!
Master cylinder is new as are the flexis, Kev the master cylinder in a Minor sits under neath the drives floor and is pretty level.
Re porous castings. It does happen, I had a mains water tap go after about 40 years in my kitchen. One quiet evening heard a slight hissss and turning on the light saw a very, very fine stream of water coming out the tap body sideways. That's only a nominal 80psi. Must have had an air bubble in there which after many years of on/off hammer decided to let go.
However a porous casting should at least give a weep if there is a weakness.
Steering woes continue, as do my smoke issue. I thought I had spotted a reason for poor timing control on the Lucas - the advance solenoid was slightly loose, so I tightened with no improvement. However, I can see some tiny little bubbles appearing out the sticky out bit on the end of it. I'll have to take photos to show where.
If it fails on emmissions I'm tempted to swap head and pump from my scrapper.
Next in line is the pinion valve. To cut a long story short, the overflow from the pinion valve should reduce /cut off when turning left and instead, there seems to be little difference in the flow at all. This would point to either a blockage preventing the pinion valve closing the relevant ports or alternatively an internal leak within the pinion valve. As both are unlikely, I'm probably completely wrong, but as I want the car to be without issues so I don't have to keep getting under it every few weeks to sort out yet another problem, then I may as well refurb my spare onion valve and see what happens!
If this doesn't work, then the logic breaks down a bit and short of bum scratching then it's a replacement of the pressure reg or pump although I think both are wild stabs in the dark.
Not sure if conventional power steering is the same but I think this is quite clever.
This was the state of the top seal inside the pinion valve. It leaked oil into the void above it which gave a path for the oil to return to tank.
Like an idiot I made a hash of rebuilding the valve using the new seals but I'm hoping I can use two of the new seals and another non leaky one.
Nice one! Surely that deserves a beer or two, at least when it's all back together and working.
Satisfying to find a real naff part as hopefully that will resolve the issue. Not knowing after a lot of work is just not the same. Handy pics for the future too.
You should of stopped right there! Already on it my friend, although knowing my luck it'll be a red herring! Pretty sure this was the problem though.
Thanks for the encouragement both........nearly there. I've just got fettling to do after the steering is working (unless that is he fails me on my grey smoke issue), but I'll have to wait and see about that one.
Yay!!! I have power steering! But the car didn't want to start. This car has a death wish I reckon! It seems that the fuel had, somehow mysteriously drained back from the pump! The clear tube from top if filter housing to the pump was full of air - I could see the fuel being drawn into the pump. That means the air must of got in through somewhere in the pump itself. I have one idea where that may be, so I'll bung some sealant on it for now to prove a point. Fingers crossed it'll prove the cause of me smoke!
That's what it used to do when i first bought it, but bypassing the fuel heater cured it completely.
Very odd it should come back!?!
Are you using the original Lucas pump?
Yeah I am. There is a leak, but oddly it's spitting out tiny bubbles rather than just diesel. I'll take piccies and show where I mean. But surely, in your case it would only syphon back if it let air in from a higher point? It also begs the question in my case as to where the diesel has gone as there is no sign of weeping diesel and there is a check valve to prevent fuel flowing back to tank!
Gonna spend the morning putting bungs back in, putting some under body sealant in various spots where it just needs touching up. Then a bit of sill work where there was small bits of rust leaving small holes. All rust treated and filled but needs finishing.
See how she ain't level with the garage door?