Author Topic: Servo Removal?  (Read 4031 times)

Offline Tav

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Servo Removal?
« on: July 26, 2014, 01:28:26 pm »
Just before I get a chance to go and look at the car I was wondering if anyone could answer following.

Fitting Mk3 servo to Mk2 is hard as nails and requires welding in a bulkhead.

But how hard is it to go the other way?  If I remove the servo and get the appropriate sized master cylinder is it a bolt on mod?  I'm working on the assumption that it might not just bolt up due to losing all that space the servo occupied.


Offline Andy

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Re: Servo Removal?
« Reply #1 on: July 26, 2014, 02:52:15 pm »
Do you want to remove the servo to gain space or to gain brake feel? If it's just the latter, leave the brake servo vac hose disconnected, job done.

Offline DaBigGinger

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Re: Servo Removal?
« Reply #2 on: July 26, 2014, 03:19:27 pm »
If the car was fitted with a servo from the factory, doesn't it need to remain in place for mot purposes?

Offline Tav

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Re: Servo Removal?
« Reply #3 on: July 26, 2014, 03:36:02 pm »
Do you want to remove the servo to gain space or to gain brake feel? If it's just the latter, leave the brake servo vac hose disconnected, job done.

Both...big trumpets! 

I don't know if your suggestion is sound? From what I can work out (not taking into account pedal ratio as I don't have a mk2 pedal to measure):

1. G40 callipers with a G40 master cylinder produce less force (520Pa) at the calliper than..
2. ...G40 callipers with a Mk2 master cylinder (694Pa for my given input force)

So the system must have been designed to work with the servo and without it would be quite poor.

Or are you suggesting...keep servo, change M/C to Mk2 and just unplug the hose?  If so that makes a little more sense but doesn't solve the space issue.  Was really open to end up servo less...just not sure what lies behind the servo and how that ties up with whats on a Mk2 (never seen a Mk2).

I'm looking into bias pedal box too but wanted to explore OEM options in the mean time.

Offline Andy

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Re: Servo Removal?
« Reply #4 on: July 27, 2014, 09:03:27 am »
All depends on how heavy you want the pedal to be, just change master cylinder to suit. Trade-off is obviously leg force vs pedal travel.

Not quite sure by what you mean about G40 m/c producing less force than Mk2 master cylinder. Do you mean per unit of pedal movement?

In my build thread there are some pics with the servo out, so you can see the holes you'd need to bolt a plate over. Fairly sure if you did that you could fit a Mk2 master cylinder or similar - some measuring required to check rod lengths and travel etc.

Offline Tav

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Re: Servo Removal?
« Reply #5 on: July 27, 2014, 11:08:37 am »
Not quite sure by what you mean about G40 m/c producing less force than Mk2 master cylinder. Do you mean per unit of pedal movement?

For a given input force by driver the Mk3 produces less force at the calliper if you don't factor in the servo.  I don't know what advantage the servo gives but I'm sure that once you factor that in the Mk3 will be superior in that respect.

My aim would be increase engine bay space, increase brake feel, retain or improve stopping power, keep 13" wheels.

It all started with wondering how to go about sizing master cylinders for a bias pedal box, which then led me back to looking at stock stuff.

Now working out what components will give noticeable improvements...i.e is it worth going to a 247 disc.  How can you package that in a 13 without upsetting wheel offsets etc.  I know the 256 was way off with RA's and the MB Racing wheels I tried...but then that was with good ol' Girling 54's.

Offline gofasterpinch

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Re: Servo Removal?
« Reply #6 on: July 27, 2014, 05:00:27 pm »
no servo on mine, bias pedal box with 0.700" F and 1" R ap racing cylinders, golf alloy calipers on the rear need more fluid hence bigger cylinder.

Offline hayesey

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Re: Servo Removal?
« Reply #7 on: July 27, 2014, 08:01:42 pm »
Dom (optima-whatever) on clubpolo did this to his mk3 GT.  I don't think it was much bother for him, if I remember correctly he had to make a fairly simple adaptor plate.