Servo removal S3

[Wangler]

I've bought a new servo on the basis that the level of assistance of the one I have (with what looks like the original servo) seems a bit low.

I thought about refurbishing it, but Pieces Fulvia are selling them for an excellent price, so it seemed a better option to simply buy one.

My question:  Is it possible to take out the old servo without having to undo the brake lines from the master cylinder? It's easy enough to take them off, but obviously involves much more work reinstalling them and having to bleed the system.

[Beckerman67]

 Yes, I managed to do it a few months back, but it isn't easy and you will swear alot!!
 You need to try to release as many of the clips holding the brake lines around the edge and back of the engine bay in order to give you the movement required to pull the master cylinder away from the servo.
 In order to make more room, I removed the heater air intake trough.
 It is then possible to manoeuvre the master cylinder forward and out of the servo being very careful not to damage the brake pipes in doing so, but clearance is minimal!
 The other problem is trying to release the servo rod from the brake pedal. It is located next to a protruding piece of bracket which renders access very difficult and you will end up standing on your head.
 You need to get to the ball join connector which is screwed onto the end of the servo rod - you would have had the option to buy a new one when you bought the servo from Pieces Fulvia.

 With your four pairs of hands, you need to depress the brake pedal to get access to the slotted end which will unscrew once the retaining split-pin has been taken out. THIS IS NOT EASY!

[Wangler]

Thank you Robert that’s extremely helpful.

I didn’t realise that the ball joint was constructed the way that it is. It’s good to know because I would have scratched my head quite a bit had I not seen it in your photo. I should be able to get a good look at it with my endoscope before inverting  myself!

[Wangler]

Update.

I managed to get the split pin out and pull the ball joint apart no problem. I’m guessing Robert’s Fulvia is RHD whereas mine is LHD which obviously must make a difference in terms of access. I also drained the master cylinder and undid the brake pipes as it just seemed easier.

What I haven’t yet worked out is whether I have to actually take the female end of the ball joint off the servo pushrod in order to be able to remove the servo. Any advice welcome.

[Beckerman67]

 You're absolutely right, mine is RHD and is a nightmare to access!
 Re the ball joint which is screwed to the end of the rod, I managed to pull mine through the hole in the bulkhead without removing it.
 Something else to consider when refitting the new servo is to ensure that the position of the joint when screwed back on is the same as the old one, hence it helps to leave it on - assuming it was in the correct position in the first place.
 Additionally the push rod end which enters the master cylinder should be flush with the casing of the servo. This should ensure that the gap between it and the piston within the cylinder is correct. If it pushes onto the piston it will result in brake binding. The one I purchased from Pieces Fulvia was set-up correctly anyway.
 I would also suggest replacing the pipe to the inlet manifold to ensure that it doesn't leak or has deteriorated. I think you would have received a new one-way valve with the servo?

[Wangler]

Excellent, thanks again. The diagram is very useful and avoids any misinterpretation.

Servo now safely out and waiting for the new one this coming week.

[Wangler]

New servo arrived and looking good.

For other people who may go through the process, the new one came with a vacuum valve incorporated into the air hose elbow banjo which was packaged separately and simply needed to be attached, not forgetting the 2 washers! The one I removed had no valve in the elbow but had one inline in the vacuum pipe. Apparently it's OK to discard the old valve and get a new piece of pipe or simply join the two halves of the old one minus the old valve.

It also came with 2 "O" rings. One fits into the groove of the master cylinder body which is pretty obvious as per the photo, but I cannot see where the other slightly larger one goes. Pieces Fulvia said that it goes "on the base of the brake pump" but there's nowhere it can fit there. When I removed the master cylinder from the servo the only "O" ring was the one fitted to the groove.

Does anyone know where the second "O" ring goes? So far as I can work out the one I've put on should provide the proper seal between the master cylinder and the servo and there's really no need for another. That's what the attached Ricambi diagram seems to show too (item no. 9).

[Beckerman67]

 I placed it here as it seemed to fit - secured with some grease.
 Number 14 on the diagram?

 

[Wangler]

Thanks, I tried putting it on the master cylinder body which I guess is the same thing, but having on “O” ring butting up against each other seems unusual. It also meant the mc would be more difficult to tighten down so it butted up against the servo without leaving a gap between the aluminium flange and the servo.

Did yours leave a gap or did it butt up as one would expect?

[Beckerman67]

 I tightened it up - rightly or wrongly!
 I agree though it is a little odd but does appear to correspond with the Manual description of parts.

[Wangler]

Thanks Robert

I think I'm coming around to your way of thinking, even though the person who attached the new mc some years ago only fitted the one "O" ring. If it were a seal for liquids I'd say no, an engineer wouldn't design it that way, but we are dealing with air seals and a servo housing that's a pressing, not a perfectly machined surface of a casting.

That said, if anyone can throw any more light on the matter that would be really good.


 

[Beckerman67]

 O-Ring part 9 description translates to: gasket between pump and servofr.
 O-Ring part 14 translates to: gasket p. plunger body

 

[Wangler]

Indeed, I had a look with Google translate when you sent the attachment.

That's the bit that now worries me. The description indicates to me a different location, it also looks to be a smaller seal on the diagram, although it's difficult to tell. The only place where the "O" ring in question fits is the aluminium body of the mc, which is in practice the same as placing it where you have indicated on your photo.

I did see a photo (attached) in an old post showing a much smaller "O" ring on a mc on an S2, but my mc doesn't have a groove machined that position anyway.

I guess the most important bit is do your brakes work properly!

[Wangler]

OK I have the definitive answer from a genuine Fulvia expert who has been working with them since Pontius was a pilot!

He told me that only 1 "O" ring is used, positioned in the groove as you would expect. He would not recommended using 2.