Hi There,

I am building a Ford Focus based kitcar which looks a bit like a MEV Rocket, I am making up a pedal box and have a few spares kicking about which includes a sierra master cylinder mounted to the servo, I was wondering if I removed the M/S from the servo and mounted it to my floor mounted pedal box with a homemade rod would it be good enough to run my brakes.
I have ford focus rear calipers and MX5 front calipers, I thought that a sierra was a big heavy car and mine will be quite light so I wouldn’t need the servo because I will not fit in the car.
Has anyone tried this or knows if this will work?

Not a good idea as master cylinders for use with servos have bigger bores than non-servoed system and also your pedals will be shorter and only have half the leverage of Sierra pedals add the lack of assistance and the brake pedal effort will be much heavier.

If you want to used tandem cylinder you need a smaller bore master cylinder --- look at previous posts but Fiat 124 is a popular choice other candidates include early VW Polo & golf without servo these cylinders are available very cheaply from suppliers such as Brakes International.

When I built the 2B I left the servo on, way overbraked and not a lot of feel. Took servo off and it was much better all round.
Most MK's are built with no servo and the Sierra master cylinder fitted, but the effective pedal is much longer than the Sierra's.

what MR Trident said,been there got the T shirt etc.
another good bit about FIAT 124 cylinders is,they use a remote reservoir

I have had a look on eBay and the FIAT 124 cylinder looks like it was fitted to a servo, is that the case or is there a version that had no M/S?

I am running 22mm sierra M/C with M16's up front and Capri drums at the back and the setup is just about perfect, I just removed the servo and ran the plunger rod directly in to the M/C.

It'll work fine without a servo on the Sierra MC but as said you will get better feel and progression with a smaller bore MC like the Fiat 124 one mentioned [this is part number BMC4020 on the Brakes International website and is less than £20].

With the Sierra MC standard brakes need a lot of leg effort.

I swapped from a Sierra 22mm mc to the above 19mm Fiat one and it was a worthwhile improvement. The pedal movement is longer but the brakes are more powerful and progressive.

Stu

it looks like i need to make a top mounted pedal box so i can have longer pedals

quote:

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Originally posted by webbey
it looks like i need to make a top mounted pedal box so i can have longer pedals

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it is a shame I don’t have a set but I also need the clutch to be hydraulic and I think the sierra is cable so I think I am back to making a pedal box, if anyone could please tell me the length of a Sierra brake pedal from pivot to the end also from pivot to where the M/S joins I will have all the info I need to get started