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MG Midget and Sprite Technical - Brake Pedal Travel Tip

Every one on this board has been so very helpful solving my various Spridget issues, so maybe I can help someome else.

I did a MAJOR brake overhaul a few weeks back. The little beast stops great, but I was never satisfied with the pedal travel. The pedal travelled too far (about 2 inches) for my liking before it met the M/C plunger.

The original actuating rod clevis was pretty well wallowed out, non-adjustable & a new one is N/A. Did a little research & discovered the 948/1098 ('58 thru '66) had a threaded clevis.

Ordered one from EnglishParts.com (p/n: 180-315, $9.73...cheap!), made up my own adjusting rod & now have perfect pedal travel, adjusted to my liking (travel now set at 1/2 inch).

I hope this will help someone...

Dave


Dave Rhine ('78 1500)

It works great! No installation or operating problems & no modifications to anything at the mounting points.

Installation photo:


Dave Rhine ('78 1500)

Now, that's all kinds of clever! Thanks for the idea.

-:G:-
Gryf Ketcherside

Dave,
Please bear in mind that there is 1/8" of free play at the pedal required. This is to ensure that the MC moves back far enough to release the pressure in it, otherwise you eventually wind up with the brakes not releasing. If your trick new rod is merely compensating for rear shoes not properly adjusted, this will bite you.
David "brake it til it's fixed" Lieb
David Lieb

David

The shoes are properly adjusted, system completely bled...this mod is to basically take the slop out of the clevis attachment point.

Also, I replaced the M/C with an after market new one & the mounting flange is a little thicker than the original. As best I could measure the plunger on the new one is now sitting about 1/4 inch farther away from the original rod.

I have between 1/4" & 1/2" play at the pedal.

Thanks for the warning,

Dave


Dave Rhine ('78 1500)

Dave,
Good. I couldn't be sure from your original verbiage whether the travel was free play before the hydraulics came into play or simply before the brakes started to do something. Didn't want you on the side of the road wondering why all your braking surfaces were glowing and the car wouldn't move ;-)
David "timid soul" Lieb
David Lieb

Yep, I've made that mistake before!

It wasn't pleasant!

Dave
Dave Rhine ('78 1500)

You should maybe check that you have not reduced the available stroke of the MC. I don't know the stroke but somebody will; the system should allow one system to be DOA and the other out of adjustment and still have brakes. It's a common error for people modifying brake systems to not consider failure modes.
You could open the bleed screws and push the pedal down all the way and see if the clevis yoke hits the cylinder body. If the reservoir is full and your helper holds the pedal down you can close the bleeds before the pedal is allowed back up, and not get air in.

FRM
Fletcher R Millmore

FRM

Thanks for the tip & you're right, I hadn't considered failure mode!

I'll check it to make sure the yoke doesn't hit the MC body & it's getting full stroke.

Dave
Dave Rhine ('78 1500)

I made something similar to prevent over stroking the clutch after fitting the co-ax kit.


Daniel Thirteen-Twelve

Daniel

Sometimes we just have do what we have to do!

I'll make sure my set up will fail safe, if not I'll keep tweaking the idea 'til I get it right.

Dave
Dave Rhine ('78 1500)

Does anyone know where I can get the type of rod that Dave has, in the UK? I was trying to adjust the free play in the clutch but the rod was seized and during the proccess of trying to free it off I snapped it off flush with the yoke. My car is a mk3 Sprite which has the tandem M.cyl.
Moss list the cylinders but not the rods, so I may have to make one, but if one was available over the counter it would be quicker as I've got alot of other stuff to do.

Bernie.
b higginson

Bernie

Try Moss part number 180-315 for the clevis.

I then cut down a long bolt with the proper thread & then rounded off the end to fit into the master cylinder plunger.

Unfortunately these simple pushrods seem to be no longer available.

I just did what I had to do to keep my little beast going.

Good Luck,
Dave
Dave Rhine ('78 1500)

FRM

Just got back in from checking the free play adjuster rod & it will fail safe. The rod pushes the plunger all the way to the end of the stroke with no interference with the housing body when bleeders are open.

It looks like a successful, safe modification.

Thanks for the caution!

Dave
Dave Rhine ('78 1500)

BRK007 from Burton
Daniel Thirteen-Twelve

Thanks guys.
Bernie.
b higginson

This thread was discussed between 22/02/2010 and 28/02/2010

MG Midget and Sprite Technical index

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