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MG Midget and Sprite Technical - Getting The Pedals Right

This sort of goes with my bleeding thread.
I've got two adjustments on pedal travel:-
1. the pushrods screwing into the forks
2. the stops
What's the correct balance betwwen the two? Should I start by backing off the stops until the pedal horns come right forward, set the stops thereabouts, and do the rest with the pushrods? Or will that result in too long a stroke?

I think when I re-assembled it, I screwed the rods right in, in order to make assembly easier, and that's where they still are, and the stops are very long. So I'm wondering if I've got too short a stroke at the moment.
Nick and Cherry Scoop

So, not very interesting.

Just for information, I did back off the stops until the pedal horns came right forward, set the stops thereabouts, and adjusted the pushrods until I had a tiny clearance. The brake fork travels 15/16", the clutch a bit less.

But the clutch is overthrowing now. It produces 3/8" at the slave pushrod without the pedal being near the floor, and I don't want to bend something in a mad clutch moment. Would it be correct to set it so that 3/8" is reached when the pedal's to the metal?
Nick and Cherry Scoop

Nick

Very interesting, I thought this has come up before, and found this (probably other threads in archive too): http://www.mg-cars.net/mg-midget-sprite-technical-bbs/pedal-box-adjustment-2016111214510629446.htm

Cheers
Mkke
M Wood

Nick

Sorry, no experience with the early pedal box.
Dave O'Neill 2

Nick,
Does yout clutch pedal have the stop protuberance on the back of it to limit travel to the floor?

How do you know the slave pushrod travel should be limited at 3/8" ?

On my other car I get 11 mm which I think is about 7/16". This is with a DIY concentric slave system cobbled together wih other parts so may not be correct but it has operated like that for 70,000 miles without problems. Maybe you can afford to go slightly over 3/8" without it overthrowing?
GuyW

Very hard to push any further, Guy. I dimly recall Paul Walbran saying that you can bend the fingers by pushing too hard. Today I will measure the throw properly.

Thanks, Mkke. That's pretty much what I've done, though the free play at the pushrod is more like 0.4mm
Nick and Cherry Scoop

Yes, it does have the stop protuberance. Explains why Laura was saying, 'it's still two inches from the floor', because she couldn't see it.

I've always believed that 3/8" was about right, but I've set it to 7/16" without the carpet. We'll see whether it works.
Nick and Cherry Scoop

I've been browsing in the workshop manual, and I came across, "Thrust plate travel to full release . . . . 0.24 in. to 0.27 in." So with the clutch fork advantage of 1.43, that gives roughly 11/32" to 3/8" at the slave pushrod.

It doesn't say "maximum travel", so maybe the pressure plate can go a bit further without bending the fingers or the clutch fork? Plus, there are three opportunities for lost motion between pushrod and pressure plate.
Nick and Cherry Scoop

I've been browsing in the workshop manual, and I came across, "Thrust plate travel to full release . . . . 0.24 in. to 0.27 in." So with the clutch fork advantage of 1.43, that gives roughly 11/32" to 3/8".

It doesn't say "maximum travel", so maybe the pressure plate can go a bit further without bending the fingers or the clutch fork?

Nick and Cherry Scoop

Nick, the figure l was quoting was for my concentric slave, so is what l get at the clutch itself. I wasn't calculating back to the movement at the outer end of the clutch fork. Is that fork advantage of 1: 1.43 what you have measured?

That figure you have found of 0.24 -0.27 is a lot less than the travel my concentric slave is giving of 7/16" which is a bit alarming! That said, my clutch has managed perfectly well for many thousands of miles on my DIY arrangement.
GuyW

This thread was discussed between 25/06/2018 and 15/07/2018

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.