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MG Midget and Sprite Technical - Triple Master Cylinder Pedal Box

I am in the process of building a Lenham Le Mans for road use and maybe a little bit of track action. I would very much like to convert the pedal box to a triple cylinder affair very much like the one that Speedwell sell in the States.

The engineering side of it presents no problems but i would like to fit the correct size cylinders for the brakes and clutch.

I shall be retaining the original drum rear brakes but will upgrade the front disc brakes slightly.

Can anybody advise what size cylinder I should go for.




mc Wilks

I believe that there is a new, unused triple m/c pedal box for sale in the classifieds at the moment.
Dave O'Neill 2

Yes I have seen that one but:
a)it is £300+ (£350 on ebay) which is quite pricey
b) the space between the brake cylinders is very small meaning there will be very little room for a balance bar adjust cable
c) it doesn't state the sizes of the cylinders.

I can make one the same as the Speedwell item for the cost of the cylinders as I have all the other components including the rod end.

The Speedwell one locates the clutch lever outside of the original pedal box which gives more room for the adjust cable.
mc Wilks

I know the answer... but im out of town for another week, when I get back home I can have a look at my set up and report back

Im using a tilton system

Prop
Prop and the Blackhole Midget

Thanks very much I look forward to hearing from you
mc Wilks

We used 5/8 cylinders with a remote tank, 11B5510 Austine Healey m/cyl is one such, and has the added advantage of a long pushrod, which gives plenty of scope for positioning and cutting to the right length to take the yoke on the balance bar.

We've made up two midget tripple pedal boxes.
For the pedal box, in the first Midget we widened the pedal hole in the bulkhead and added reinforcing ribs to make up for those cut into.

For the second Midget, we've kept the original hole and Adapted the pedal box design to suit. This required the clutch pedal to be offset from the cylinder by quite a bit, but was reasonably simple to accommodate, certainly simpler than modifying the bulkhead.

Sorry, the photos are sitting on a hard drive currently 150 miles away ...
Paul Walbran

Unfortunately... im still out of town and will be for another week at the least
Prop and the Blackhole Midget

Thanks for your comments, a picture if you can get hold of it would be great.

No problems Prop I'm not in any great rush got loads to keep me busy
mc Wilks

Well after a bit of machining and filing I came up with this - its just dry built at the moment as I need to do a little more machining on the two 5/8" cylinders (remove some of the top lug material)

It will then be powder coated and connected up using two remote cylinders for the front and rear brakes.

There is a small amount of adjustment on the bias for the brakes which I will adjust with a cockpit mounted adjuster.

The total cost for the whole unit was £138.00 all of the kit except the original pedal box came from ebay and all the items were new.


Martyn Wilks

What cylinders did you use?
J Bubela

Clutch is a Wilwood 3/4" and the brakes are Tilton 5/8"
Martyn Wilks

Martin I apologize, I got so side traked on this out of town job I completely forgot about you... nice set up

3 FYI's..

1. you will need a 90 degree elbow at the end of the master cly to hook up the brake pipe to the angle of the sheet metal plateform of the car is to steep and wont allow a straight connection

2. You really want to invest.into stainless steel braided lines because there flexable and can be moved around with ez where as fabbing contortion hard brake pipes ... is not a fun day at the office

3.. you can connect a pressure switch inline to activate the brakes light... summit racing /jegs

Prop
Prop and the Blackhole Midget

Opps ... I forgot, a

4th FYI.... It wont fit !!

This is a 2 parter.... the problem is the width

Part 1 the clutch master cly cap will foul the rain channel of the wing, easy solution is to notch out the rain channel and reinforce it ... but thats on the tilton set up and a weeks worth of measuring and planning

The 2nd part of FYI ... it wont fit

is because if you widened the box for the 3 cly to fit into there is an issue with ither it hangs off the base its bolted to or severly bangs into the wing where a little trimming of the rain channel wont be adequate.

The solution was to hang the master clutch cyl off the side of the orginal box and not encapsulating it

Sorry

Prop

Prop and the Blackhole Midget

Look up a dear old ghost and great friend in the archives named Bill Young, ... he did this project and lays out very well about the width problem and has photos for his work around on using the orginal peddle box

Telling Bill I said hello, and I miss him

Prop
Prop and the Blackhole Midget

Hi Prop

Couple of things to note

It will fit because:

a) it is a right hand drive car and will have a Lenham bonnet so no rain channel to get in the way.

b) I didn't widen the existing pedal box - instead I got it all to fit in a standard one with a bit of lateral thinking.

Both the clutch pedal and the brake pedal are in exactly the same place as they would be with the standard layout. I moved the clutch push rod position to the far side of the pedal box by using a clevis mounted on the outside of the pedal thereby gaining room.


I am going to use all stainless steel braided hose with an inline brake light switch and I will be using banjo fittings to connect to the cylinders.

I copied the attached picture which was allegedly a Peter May one.


Martyn Wilks

This thread was discussed between 13/10/2015 and 19/01/2016

MG Midget and Sprite Technical index

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