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S4 Brake servo location

PostPosted: Mon Mar 30, 2020 9:25 pm
by vxah
Can anyone help me with some measurements to mount the brake servo bracket to the inner wing? I have replaced the n/s front corner of the body and unfortunately seem to have binned the old part prematurely!
It’s difficult to offer up the bracket as it has studs that stop positioning before making holes!
While I’m at it, where exactly should the wiring harness clips be located down the n/s inner wing?
Thanks very much.

Re: S4 Brake servo location

PostPosted: Tue Mar 31, 2020 10:47 am
by oldelanman
It's difficult to get any meaningful measurements from a fully assembled car, the mounting studs are visible in the wheel arch but there isn't really any suitable datum point to measure from. It's also likely that position will vary slightly from car to car, particularly if replacement panels have been fitted. I don't think the position is critical but you do need to make sure the booster can clears the headlamp vacuum pod.
I suggest you fit the headlamp vac pod first then offer up the servo assembly with the mounting bracket attached and find the best position which gives clearance, a dap of white paint on the end of the studs will mark the positions of the holes. My servo is pretty much horizontal with around 10mm clearance to the vac pod and the mounting bracket positioned as far back on the wing panel as it will go but I don't know if this is typical.
Happy to try to take some measurements under the wing if you think it will help but as I said they may not apply to your car.
Servo mount bolts.jpg and

Re: S4 Brake servo location

PostPosted: Tue Mar 31, 2020 11:37 am
by vxah
Thanks for the information, I’ve managed to get the vacuum pods fitted now so I’ll try and offer it up!
I did think about leaving the servo of as others have done but, I would hope the mrs will drive it and a solid brake pedal might be a mistake?

Re: S4 Brake servo location

PostPosted: Wed Apr 01, 2020 8:38 am
by alan.barker
What Servo are you fitting because replacement ones need to be orientated correctly to stop the Brakes locking on :shock:
You may need to make a Custom Bracket.
Alan

Re: S4 Brake servo location

PostPosted: Wed Apr 01, 2020 12:50 pm
by vxah
I believe that the correct one for a 69 S4 would be a Girling MK2a? I have one in bits but it could do with a sleeve fitting.
It seems my local guys are still working so they are going to do the machine work for me and I will build and fit it. I can always bypass it to try if I don’t like it?

Re: S4 Brake servo location

PostPosted: Wed Apr 01, 2020 1:10 pm
by alan.barker
If you fit +2 Calipers and +2 Discs you don't need a Servo
Alan

Re: S4 Brake servo location

PostPosted: Wed Apr 01, 2020 2:44 pm
by oldelanman
vxah wrote:I believe that the correct one for a 69 S4 would be a Girling MK2a? I have one in bits but it could do with a sleeve fitting


Depends ..... S4 used the MK2b from chassis no 9325 onwards.

Re: S4 Brake servo location

PostPosted: Wed Apr 01, 2020 2:52 pm
by Elanintheforest
Here's mine in situ. It has the 2b type with the band around the tank, but with the larger 7 inch diameter tank, which worked very well apparently. You can bypass very easily if you don't like it or it fails!

The second photo show the area with the servo removed, which doesn't help much! You can just make out the 3 mounting holes for the servo bracket. I'll put the bracket back on and take some photos and see if I can get any meaningful measurements.
Mark

Re: S4 Brake servo location

PostPosted: Wed Apr 01, 2020 6:17 pm
by vxah
Thanks Mark, I’ve now fitted the bracket, going to run the pipes to the servo then take it off for rebuild.
By the way, any concerns about an electrical fire? Sorry :?

Re: S4 Brake servo location

PostPosted: Thu Apr 02, 2020 7:21 am
by Elanintheforest
I haven't touched the wiring yet, and there is a bit of tidying up to do. But the cables are still flexible and with a bit of loom tape will go again!