S50/M50 brake servo size's needed please!

[tomson]

Right, I've been looking for about a month now fow a suitable servo, either VW or Renault for my S50 swap. I've been pestering seller's on Ebay to actually measure the servo for me as I don't want to buy the wrong size (I've bought 3 which were wrong already ) and everything is coming back at around 230mm which is only slighter smaller than stock E30. So my question is this, is this the right size-only around 25mm smaller than stock? I'm sure I remember reading some where they are around 200mm ? ?

Can you guy's that have done this mod actually measure your servo's for me pretty please as I'm beginning to think I'm looking for something that doesnt exist!

I am moving the servo over as per Dameon did on his S50 swap, I have the dash out now and want to do this as soon as I get the servo, so it's holding me up a tad!

[Jhonno]

I think if you move it over enough even the standard servo will fit!

A plastic wing clio servo is what you want.. Someone did a pic comparison recently on here vs. the E30 one!

[E30BeemerLad]

I will measure mine tonight for you dude, it's a clio servo, not entirely sure of it's origin as it came with the pile of M50 scrap that is in bits in my garage at the moment. There is a clear difference in size to the original E30 one though

[tomson]

Really, interesting info on the stock servo! I think it's moved 65mm from memory using Dameon's plates but dont quote me on that!

Yeah I'm aware of the plastic wing servo but they dont seem to be much smaller than stock?
Jonb is currently doing an M50 swap and I've seen the clio servo he bought and it's not much smaller than stock, ok on a M50 but I think it may still cause issue's on the S50 plenum....

I remember that pic your on about and they did look alot different in size.......

[tomson]

That would be ace E30beemerlad, measurements are needed!

A clear difference in that photo although the E30 one is closer to the camera...

[jaffro]

i used a golf servo think it was mk2 1.3. i got it off toby unna a it was a lot smaller than bmw servo

[zimmerbimmer1]

If I remember rightly old_skool_2002 used a 1.3 golf servo and moved it across 57mm. I think he made a template for future conversions or if any one else wanted one.

[DanThe]

I have 200mm in my mind for the clio servo, beemerlad will confirm later though

[tomson]

Yes Dameon used the Mk2 1.3 golf servo but try finding one!!!

I have made a copy of his plates to move the servo over as he kindly loaned me one of his spare's.

[tomson]

Yes 200mm will be ok for the S50 I believe but all the sellers on ebay are coming back at around 230mm so I'm guessing there are different one's on different clio's...

[Reeeedish]

Hi Tom,
After I popped in last week I called in at Whitehouse VW on the way back (armed with my E30 servo). Had a look at what they had......

E30 on the left Golf mk2 in the middle Polo G40? on the right



I bought the Golf mk2 (middle) one and installed it a few days ago.
I made my own plates up in the end and moved it over 55mm












I've just measured the Golf mk2 servo i'm using and it is 225/230mm

So as long as you move it 55mm or more you should be ok. It's tight getting the air collector on and off but never mind.

Whilst we're on the subject of S50 braking. Would the standard Audi 23.81mm master cylinder be ok to use? Currently my brakes (size of discs) are standard.
Am I right in saying that people generaly go for the 'ZV25' (25mm) master cylinder if they have upgraded to bigger brakes?

Cheers
James

[tomson]

Hey James,

that servo is too close for my likeing, will cause problems on hard right cornering I'd imagine?

I'm moving my servo over the same as Dameon did on his, which looks very similar to yours but his servo is definately smaller,

http://www.e30zone.net/modules.php?name ... c&start=50

scroll almost halfway down that page and you will see the difference. I might pop up Whitehouse for the other servo in your picture as that looks about the right size!

How much did they rush you for the 16v servo mate?

As far as I'm aware the 25mm Audi M/C is used to compensate for the smaller servo on standard brakes, it's what I have to use in any case. I want the car up and running before I mess about with bigger brakes and I have E30 M3 stuff to go on......

[Jhonno]

23mm Audi master is far more suited to standard e30 brake setup than the 25mm..

[DanThe]

I have a 750i master with a clio servo and its not good, servo just hasnt got the guts for such a big bore.
Will be changing back to a standard E30 unless I can find the right Audi one soon,

What are the markings to look out for on the Audi one?

[tomson]

What are the markings to look out for on the Audi one?

They have a stamp on the top or bottom of the casting where it bolts to the servo, 23 is 23mm, 25 is 25mm etc etc. They won't all say "ZV" after the number as this is the manufacturer and Audi had a few suppliers although the majority of them are "ZV"
Mine does say "25ZV" on it though....

[E30BeemerLad]

Tomson, sorry dude, I forgot to take some measurements of the servo last night, promise I will do tonight and post up details.

[ian332isport]

As far as I'm aware the 25mm Audi M/C is used to compensate for the smaller servo on standard brakes

Servo size and master cylinder bore have no relationship. Master cylinder bore is only dictated by the mechanical pedal ratio, and the piston area in the calipers. Servo size only dictates the amount of assistance that is provided. It doesn't change the pedal travel, or the ability of the braking system to stop the car. It just means YOU don't have to do as much work.

You only need to change the size of the master cylinder if you change the piston area in the calipers (larger multi piston calipers etc).

Ian.

[DanThe]

Well that poxy little clio servo is a lot stronger than my leg! The rubber seal was broken originally so the vacuum was leaking, stopping ability was atrocious, I could literally stand up on the pedal with both feet and it made no difference!

[eko]

3 M50`s here all using the Clio servo.
Benjys and mine are both with standard E30 M/C and OBs is using a 23mm Audi M/C.
Ive driven all 3 cars and there is very little difference between them to be honest.
Personally id advice using the Clio servo over the Golf one,pedal feel is so much better!

[DanThe]

I used an E30 master with clio servo on Radish's cab and the brakes were better than standard

[E30BeemerLad]

just had a measure of the servo on my car, difficult to so when it is fitted, but in rough figures you are looking at about 22cm across the middle

[Reeeedish]

Thanks for all the clarification guys. I will be hunting down a 23mm M/C for the time being then (standard calipers/disc size)

Tom, seems like a few of them are 225mm servo's. Matey at Whitehouse took me for £30. I think it was roughly the same for that smaller Polo G40 one (well so he called it anyway). I would think about going for the 225 Golf servo (readily available), but just move yours over 60mm, there is just about enough room.

I'm hoping to be out for Combe (6th), you coming?

James

[dicko]

I have a clio servo and standard MC and the brakes are better now than with the standard servo ?
I cant figure out why the clio servo is a lot smaller than the e30 servo .
Even my wife can lock the brakes up thats how light they are .

[tomson]

As far as I'm aware the 25mm Audi M/C is used to compensate for the smaller servo on standard brakes

Servo size and master cylinder bore have no relationship. Master cylinder bore is only dictated by the mechanical pedal ratio, and the piston area in the calipers. Servo size only dictates the amount of assistance that is provided. It doesn't change the pedal travel, or the ability of the braking system to stop the car. It just means YOU don't have to do as much work.

You only need to change the size of the master cylinder if you change the piston area in the calipers (larger multi piston calipers etc).

Ian.

I knew you'd be along soon Ian to set it straight

[tomson]

just had a measure of the servo on my car, difficult to so when it is fitted, but in rough figures you are looking at about 22cm across the middle

Cheers Fella

[tomson]

Tom, seems like a few of them are 225mm servo's. Matey at Whitehouse took me for £30. I think it was roughly the same for that smaller Polo G40 one (well so he called it anyway). I would think about going for the 225 Golf servo (readily available), but just move yours over 60mm, there is just about enough room.

I'm hoping to be out for Combe (6th), you coming?

James

Hmmm, I will on this again next week now so I will see what he's got at Whitehouse then.

Yes I'll be at CC on Saturday, going to Paul's 1st for a dyno in the sport and my first laps are 12.30 iirc. See you on Saturday James