Brake Booster Replacement - a Hint

[geoff]

well I am now putting things back together - and what a journey it has been. What have I learnt?.
It is strongly recommended to remove the seat first.
Then remove the master cylinder, then undo the servo - but remover the backing plate from it prior to trying to remove the servo from the engine bay. (You may need to buy a box spanner of 13mm. with a right angle bend). Then even more fun..................try to wiggle the servo out of the engine bay.
It is a bas**rd but can be done without removing any cables or hoses!
Many have said that the backing plate is not symetrical so mark the top if it to aid refitting. (I am not convinced about this myself, but decided to fit it in the original position anyway).
The reinstallation is the reverse of the above - but with the addition of the need to obtain some touch up paint to repair all of the scratch damage to the paintwork in the engine bay and then clean off the footprints from the back seat before my wife sees them and assumes that my spider really is a babe magnet !
I also recal one of the first comments of this thread "if you feel that the servo is failing - sell the car "

[courtenay]

Well done!! Getting the top right nut - the one the pedal spring bracket is attached to - was a lot of fun, right? As was reattaching the spring.
If you find you can’t get the front brakes to bleed, it may be because the plunger that comes out of the servo OS too far out....happened to me.
Good luck with the rest of the mission!

[maxm50]

Hi all,
I'm embarking on this journey of booster replacement myself tonight.

For the top right bolt that everyone is complaining about, I found it quite easy to remove AFTER first removing the black box that blocks line-of-sight to the bolt. I believe it's the O2 sensor mileage counter? Anyway, just two 10mm nuts hold that thing on. Move it out of the way and you have a clear sightline to the bolt, and a simple wobble extension (or regular extension + U-joint) will let you get it off.

Now, I'm stuck at removing the booster from the engine bay. It's hitting the fuel rail hard connection closest to the firewall and I can't finagle it past there. Is it easier to just remove the fuel rail? I have a 1981 FI Spider.

Or, is this when I should try removing the mounting bracket in-situ and pulling the booster upwards (?) around the clutch cable? Seems difficult.

Any other tips? If I remove the fuel rail, is there anything I should know beforehand? (ie. have an extra gasket handy, replace all the injector seals because they won't seal once you remove them, anything like that?)

Thanks!
Max

[spider2081]

should try removing the mounting bracket

I found out the hard way the black booster mounting bracket is not symmetrical. I now know to mark it before removing so I don't install it upside down on the replacement booster.

[geoff]

I did not remove any cables or hoses at all. I recomend removing the backing plate before trying to remove the servo (I bought a 13mm. right angled box spanner for this) . If your car is in good shape, I suggest trying to line the nice shiny paintwork on the wheelarch with something strong but thin - perhaps some tough nylon or plastic sheet in order to reduce the scratch marks you will make when you get angry pulling the ba##ard out. I did not do this and very much regret it.

[courtenay]

I didn’t remove the fuel rail. I did disconnect the fuel line to it And moved it out of the way. I also removed the backing plate from the servo. Then it was twist, turn, pull and swear a lot to get that frigging bugger out....only to reverse the process to get it back in.

[maxm50]

Alrighty, thanks for the input guys. Removing the backing plate in-situ looks harder to me than removing the fuel rail, so I think I'll just do that... I've been meaning to replace the 30-year old hoses and fuel injector seals anyway, so I guess now is as good a time as any!

Isn't that always how these jobs always go? Repairing an emblem somehow can turn into an engine overhaul. Scope creep...

[geoff]

keep us posted maxm50.
I have just put the seat back in and connected the master cylinder so will now start the bleeding process. The thing that I hate is doing damage to my car in the name of replacing parts - and I scratched the original paintwork because I did not a)remove the backplate first, and b) cover the wheel arch with something to protect the paint.
geoff

[maxm50]

Well, I finally got the fuel rail off. The electrical connectors are a huge pain. Does anyone have a good method or tool for removing those things other than a tiny screwdriver and lots of swearing? My method was to put a little tension on the wire, use a screwdriver to lift up one side of the metal clip, get that side wiggled off via pulling the wire, then move the screwdriver to the other side and lift up the metal clip and off pops the connector. And pray that the first side doesn't pop back on in the process. Not so bad on the first 3 cylinders actually, but good lord, removing the electrical connector to the #4 fuel injector (nearest the firewall) was an absolute nightmare. I found that I had to pull all the injectors out of their seats, get some slack in the wiring harness via removing the hold-down on the intake manifold, and pull the whole thing out and twist that #4 injector up in front of the brake booster to get enough room for my hands to get the clip off.

Basically, I want to punch whoever designed these electrical connectors. They're a big enough pain when totally accessible (AFM, coolant temp sensor, cold start injector) but an absolute NIGHTMARE on the fuel injectors where access is limited. The design is slightly different so that you can't first dislodge the metal clip and THEN pull the connector - you have to do it all at the same time because the metal clip is retained at the top. These things are clearly designed for easy installation with no thought towards easy removal. And it's pretty clear that the FI system was tacked-on to an engine bay never designed for it... obviously.

Anyway, enough ranting. Turns out it was a good thing I pulled my fuel rail for this brake booster replacement, because the fuel hoses show cracking when bent, and the injector seals are laughably mis-shapen. I'm sending the injectors to Fuel Injection Corp today for full rebuilds and flow testing, just received new seals from Autoricambi, so at this rate by sometime next decade I'll have a functioning brake system again. My wife asked the very valid question today of why fixing the brakes requires a fuel system overhaul.

I'll make a more relevant post to the original topic once I pull/reinstall the brake booster now that the fuel rail is out of the way, so that others can know if this is indeed a good way to do it...

[geoff]

maxm50, what are you talking about?
Sorry, I don't mean to be rude but we must be talking about different engines here. Mine is a 2.0L bosh injection and I have no idea to what you are referring here.
please would you be so kind as to clarify what electrical connectors you refer to.
cheers
geoff

[maxm50]

maxm50, what are you talking about?
Sorry, I don't mean to be rude but we must be talking about different engines here. Mine is a 2.0L bosh injection and I have no idea to what you are referring here.
please would you be so kind as to clarify what electrical connectors you refer to.
cheers
geoff

Hi Geoff, no worries, happy to clarify. I'm talking about the electrical connector to each fuel injector. They must be removed if the fuel rail (with injectors connected) is to be removed from the engine bay. I guess it might be possible to leave it connected and place the fuel rail atop the engine temporarily while working on the brakes... but since I'm replacing all the fuel lines while I'm there, I just removed the whole fuel rail to my benchtop. Let's just say I'm quite happy to be done with this part of the job!

[maxm50]

Update:
Removing the fuel rail made the brake booster removal/reinstallation quite easy. If doing it again, I wouldn't do it any other way.

I also pulled the charcoal canister (2 nuts) for better access and used the opportunity to replace the vacuum hose underneath it. Also lubricated the clutch cable by undoing it at the transmission, pulling it up, hanging it vertical and slowly dripping TriFlow cable lube down it. Also getting all 4 injectors rebuilt by Fuel Injection Corp. Also replacing all brake lines with SS lines. A real snowball of a job!

Not quite sure I got the acorn nut set correctly yet. I haven't tried bleeding the brakes yet. I used a "guess and check" method to set it while the MC and booster were on the bench. I set the acorn nut out far enough so that it slightly engaged the MC when pressing the two together (you can feel it). Then I backed it off just beyond the point that I could no longer feel it engage the MC cylinder, then bolted the MC to the booster. My thinking is that this is a good way to get a minimum possible gap and should be at least as accurate as careful measurement (which I also did, but hey, I like functional checks). Hopefully I got it right!

[RRoller123]

I found too that removing the fuel rail was the best way to go. Opens up a lot of room, can clean up and inspect other stuff under there.

[SteinOnkel]

I'm 90% sure I had the whole intake off when I did it.

It's amazing how cramped these cars are compared to their similar vintage brethren. Signore Agnelli, why you hate mechanics!?

Also when you have the booster out it's an excellent time to weld an extension onto its bracket and put the clutch cable's grommet through it and not the firewall. It's not a question of if, but when the firewall starts to crack.

The acorn nut can be adjusted on the car. You probably will have to, they never bleed right the first time. It's a stupid design. Basically you just need to remove the two m8 nuts holding the mc in and yank on it hard. That will give you enough clearance to reach it in situ. The brake lines have enough flex for that.

Never understood why people think braided brake lines are better. The cheaper ones have the disadvantage that the inner rubber deteriorates and you can't see it. Very dangerous on brake components.

[geoff]

well here we go......................all back together but not able to get any fluid out of the brake line !!
When I reassembled it all I screwed the adjustable plunger nut right in (so it was flush with the servo) so do you think this needs to be screwed out a little. Is there any guidance for this adjustment?