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MG Midget and Sprite Technical - 65 to 67 pedal box swap

Hello all,
I am working on my 65 Sprite and intend to install a
1275 engine that amazingly started on the first crank after sitting for 8 years(67 midget donor car).
Should I swap the the pedal box/master cylinders to the 65 as well? Are the the early 1275 single line masters any better than the combined brake/clutch system? I am about to order parts for a complete brake/ clutch rebuild ( new seals,lines, fittings, hoses and bleeders)
so I am wondering which system is better.
Thanks Bob
R.W. Davis

if the sprite had disc brakes to begin with there is no harm in using the combined MC

the bore sizes are the same as the split system

but the parts for the combined ar a bit harder to get a hold of
Onno Könemann

Thanks Onno,
I thought I had better check with the experts and the combined wisdom of the ages ( although an hour in the archives didn't turn up much on pedal boxes except a lot of great info on bleeding the hydraulics ).
Bob (hoping to get on the road soon)
R.W. Davis

Also bear in mind you need major surgery on the panel to fit the later pedal box as it is wider, so if your twin is in good condition then keep it.
Graham.
Graham P 1330 Frogeye

Bob,

If you do get into modifying to fit a different pedal assembly, you might consider putting in the newer dual line brake master system. I put one in my 65. I don't know the exact year of the donor car, but it is the master with the big round cap.

Charley
C R Huff

Thanks all.
I may have to use the separate masters/pedal box after all. I fought with the twin cylinders all weekend trying to get the pistons out - tried air through the outlet fittings and lubing up with everything from brake fluid to alcohol to CLR(weak acid to remove calcium scale) to
various penetrating oils. Tomorrow I'll see if I can get some grease nipples to fit the outlets and pump them out with grease. Even then it may not be worth saving.

The '67 midget just had the single line brakes and would take a bit hacking and patching to fit this is the stage to to do it since I haven't painted/ refinished the interior yet.
Bob
R.W. Davis

I intend to install the separate cylinder system, in the main because of my over heavy clutch pedaIt was heavy even before I installed the concentric, its no lighter now

After I return from Le Mans
Bill sdgpm

Depending on how much work you are willing to do and how much body modding is acceptable you might be better off buying a new twin cylinder.

To fit the singles you will need a later pedal box plus pedals, springs, etc and two new cylinders which I believe will cost you more than just a new or rebored/sleeved twin cylinder.

Fitting the new box requires cutting out the two thin angle iron ribs under the top footwell panel as the pedal box is wider, making up two new ones to replace them and re-stiffen the panel. The ribs really need to be drilled and have captive nuts welded on to make life easier fitting the new pedal box. You will also be left with a damn great hole which will need plating either on the body or on the pedal box as the later box is not filled in like the early one but just has two ribs extending rearward which bolt down to the footwell panel. It isn't actually difficult, just time consuming!

Alternatively I have seen later cylinders fitted into an original/ modified box, they were a tight fit but somehow the guy got them in and it looked good with no mods being done to the bodywork.

I modified my frog's tunnel to fit the later box, but only because it had already been butchered by the PO and I managed to get a later bedal box with pedals etc for a very low price plus a NOS brake master cylinder for £20-00. For me it was worthwhile as the footwel had already been badly modified, the brakes were apalling and I got the parts cheaply enough. If the damage hadn't already been done then I probably would have gone for a new twin cylinder.
Graham.
Graham P 1330 Frogeye

Just in case you are interested, this is the abortion that was fitted when I got the car. A mini dual cct master with a servo fitted to the fronts plus a pressure limiter fitted in place of the "T" piece at the rear, as may be aguessed, the brakes worked very poorly!!!!!


Graham P 1330 Frogeye

looks tidy Graham, shame it was poorly engineered; BTW what happened to the heater blower unit?
David (davidDOTsmithAT stonesDOTcom)

He fitted a carb cooling fan from a Fiat X19 in the trunking, guess what! That didn't work very well either! Now "restored" to Mk 4 fan.
Graham.
Graham P 1330 Frogeye

Well I guess I have a Pyrrhic victory of sorts: I managed to get the seized pistons out using the grease gun but the springs, pistons, and the rest don't appear to reusable. I'm not going to bet my life on the master cylinder casting either.
If anyone wants to try this truly messy operation:
I packed the reservoir with grease,made a cover gasket
with top quality cereal box cardboard (covering the fill hole) and but the cover on tight. Then I soldered a 3/16"
grease needle fitting to the drilled out outlet line fitting (see image).Block the other outlet with several rounds of teflon tape over the other outlet fitting, then connect the grease gun and pump like no tomorrow.
Then switch outlet fittings and do the other side.

I think I'll investigate Graham's idea of putting the separate cylinders into the original pedal box. At least they still have brake fluid in so should still be rebuildable.


R.W. Davis

Bob, I'll try and contact the gut that did it, he's in the AH club and lives locally so I'll try to get hold of him and ask him how he did it,
Graham.
Graham P 1330 Frogeye

Archer's Garage do them, see here
http://www.sebringsprite.com/price_list.htm
David (davidDOTsmithAT stonesDOTcom)

Thanks again. It's good to know it's been done before.
I haven't seen the Archer site before. Their pedal box
looks like a nice neat assembly. The master cylinders they use don't look any of the originals in the catalogs and manuals I have. The way they have staggered them with one longer push rod and front mounting plate certainly looks achievable. I did see these Tilton master cylinders ( http://www.tiltonracing.com/content.php?page=list2&id=25&m=b )
but I'll try the originals first.
R.W. Davis

Bob, you could also try Gerard's Garage who remanufacture twin bore clinders, here is a link: http://www.gerardsgarage.com/Garage/Tech/DbrakeUg.htm they aren't cheap but I believe they have a good reputation.
Graham.
Graham P 1330 Frogeye

This thread was discussed between 23/05/2009 and 27/05/2009

MG Midget and Sprite Technical index

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