16 replies to this topic

[Bam]

How do you fit a brake servo, im doing a drum to disk converstion and I am going to fit a servo.

Thanks

[minidaves]

i worry on here sometimes because its a nut and bolt job u need to change almost everything in ped on pedal box, engine steady plate etc

takes a couple of hrs

dave

[Bam]

i worry on here sometimes because its a nut and bolt job u need to change almost everything in ped on pedal box, engine steady plate etc

takes a couple of hrs

dave

What?

What do I have to do?

Thanks.

[Dan]

You will need:
New servo type brake pedal or complete servo type pedal box.
Servo type master cylinder mounting plate.
Pedal box extension / bell crank housing.
Servo.
Inlet manifold with servo connection.
Servo hose with one way non return valve (very important).
Servo type master cylinder.
Master cylinder brake lines.
Two nylon coated clevis pins of the right size for the bell crank, split pins, washers, nuts bolts and screws, new M/C baseplate gasket and general stuff for fitting.


(If it's LHD you'll need a bit more junk)

Remove your brake pedal or the entire pedal box if you are doing it that way (much harder) and replace with the servo type one. Remove both master cylinders and their baseplate (which also holds the steady bar in place) and replace the baseplate with the correct new one having fitted a new gasket and some gasket sealant. Ensure the rubber bellows on the pedal is engaged with the baseplate if you want to avoid water leaking into the car. Locate the pedal box extension over the studs and mark where the upper stud hits the bulkhead. This should be in the Mk bonnet hinge depression. Drill the hole and paint the cut edges. This should be a position for a welded nut as standard but you can use a normal nut and a couple of large mudflap washers to spread the load. You may need to make this dent a bit deeper to get the servo to sit at the right angle, don't do it yet but be ready to. Now fit the remaining parts together and re-build and bleed the clutch system Actually, bleed that before bolting the servo in place. Bleeding it later is a nightmare. The pedal height is adjustable by winding the servo rod in or out. Make sure you can get full travel of the MC pushrod before reassembling the brake system. Connect the servo to the inlet manifold with the valve the right way around. Connect up the brake lines and fill and bleed the system. Flexible lines are available for here and make future servicing much easier.

The most important part of fitting a servo is to make sure the hydraulic design of the brakes is up to scratch. By which I mean make sure you are using the correct rear wheel cylinders. The servo MC is a smooth bore I think and so it sends more fluid to the rear brakes than the earlier stepped bore cylinders do. You need to make sure that you are using the correct size of cylinders here to keep the braking balanced. That is the hard part.

You will notice almost no difference to you braking having done all this work.

Edited by Dan, 03 July 2006 - 07:56 PM.

[Sprocket]

you will also need to move the pressure reducing valve into the corner near the inner arch.

I found out the hard way by trying to cheap skate it. Im doing the servo to standard master conversion ( the servo takes upto much room IMO). Removed the clevis and push rod from the pedal to find the hole is bigger, also the metal is thicker, went and got another pedal, only to find the the hole in master cylider bracket/ base was not big enough, spent 15 minutes with a file to get it to fit, only to find out that the mounting holes are not inline with the big hole, went and got the right bracket, only to find the brake pipes i had wouldnt reach the pressure reducing valve, ended up moving that and bending the main brake lines to get them to fit, only to fint that one of the brake lines is knackered. Needless to say I was not a happy bunny.

Other than drilling a couple of holes, and if you have all the right bits, its just a bolt on job. Oh and if you have a 1275 with the breather on the transfer casing then you will also need the funny squiggly breather canister as well.

[Bam]

Is it worth it?

My brake set up is:

Front:

drilled and groved disks.
EBC pads.
standard calipers.

Rear:

finned drums.
new shoes.

Will a servo make much diffrence as i thought that a servo was there to make braking easier not better.

Thanks.

[miniboo]

nope i wouldn't bothre for the extra hassle and the space it takes up. It doesn't inprove braking it just makes it easier. less force needed on the pedal for the equivalent braking power.

That made more sense in my head!!

[Sprocket]

Servo gives a shorter pedal travel and makes the feel of the pedal less spongey

If you leave it then at least make sure you fit the correct Master cylinder with the stepped bore. It'll save space and some weight

[Guess-Works.com]

Quite simply,, unless you are seriously deficient in the leg muscle department, don't bother... a servo does not improve the braking, just means you need less foot to push the pedal....

like power steering....

[Bam]

I dont think ill bother fitting it then.

Ive just converted from drums to disks so i think that my new brakes will feel amazing.

[Guess-Works.com]

Well.... there's thre in a row...

[Pooky]

But if two minis were driving at the same speed (one with a servo and one without) and applied the same force to the pedal, who would stop first?

I'm wondering whether to put a servo in my estate project, the plan is making it a comfortable car...

[miniboo]

propably the one with a servo but only because the same force is used and it will be multiplied through the servo.

[Guess-Works.com]

lazy leg

Ah ps.. if you stamp on the brakes in a servo equipped car, the force you apply is more than the servo anyway, so it becomes redundant !

Edited by GuessWorks, 04 July 2006 - 08:59 AM.

[miniboo]

ah right ok i see