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MG Midget and Sprite Technical - Brake/clutch master

Hi,

My first post over here.
I restored my 63 Sprite in 1994. It's an HAN7 1100 cc with disk brakes. When I restored it, I convert it to silicon brake fluid. Having a rally on Saturday, I check the car today and ... the brake/clutch master is leaking. Not a big deal I was thingink : I've a new brake cylinder in my parts stock.
But... This one turned to be the 7/8 bore model. I presume I can't use it on my sprite ? Can somebody confirm.
Too late for a real rebuilt so I'll try just replacing the rubbers
µ
Also, as usually, the mechanical fuel pump is leaking. Allways the same place : the outging pipe where the olive, even new is not effective. Is there a chemical (pasta, silicone, thread locker) that could help and be fuel resistant ?

Regards
Spyros

Spyros,

I have used a 7/8" master with discs on my sprite for a few years with no problems that I was aware of. I rebuilt the sprite in 1984-5 and kept the 7/8" master and fitted disc brakes before it reached the road. I have subsequently read that you should do some mods, remove a valve from the master cylinder?, all seemed to work well for me. Others may inform you what you should do.

Regarding the fuel pump something must be defective in the seal area, seat, olive, tube surface. See if something regarding the machining detail is preventing the olive properly clamping to the tube or fully compressing the olive.
David Billington

Hi Dave,
Thanks for this info. I might try then my 7/8" brake cylinder.µ
µ
For the fuel pump, it's not the seal, nor the olive but as you said I don't believe that the olive is corrctly compressed. I'm using a repro pump. I had to change the one on the car some years ago and found that it was already a repro. These are not of a good quality : I had to reuse all the screws of my old pump because the new ones are too long. I already replaced the tube and the olive and ended up shortening the retaining nut hoping to allow it to go more into the pump but no hope... this leak is allways coming back
Spyros

David is right. They can be used (expect a little less pedal travel) and remove that plastic thingy from the master bore. Thats a sort of anti returnvalve that keep the pads of your diskbraked car allways "on".

The best way to deal with a mechanical fuelpump is to replace it with an electric. Buy yourself a blanking plate for the hole in the casting and mount the right pump at the rear of your car. If you add the fuel pressure regulator you can buy any pump that pushes. Thats very effective when your pump has to be replaced. Any pump at any price can be used when you have a pressure regulator.
Bas Timmermans

The new brake/clutch cylinder will be on the Sprite in about 1 hour.µ
For the pump I keep it mechanical µ
2 scenarios : µ
1)fit a pump coming from a mini (easy to find quickly)but any problems there ?µ
2) replace on the pump the little pipe and olive by a nut incorporating the pipe. (I've a couple of these for another project , matra engine with a golf 16 v head) but this will depend on the threadµ
3) bodging with loctite ..., temporary fix
Spyros

Well at least the fuel pump is fixed. Some angle grinding on this repro part and the nut was allowed to go more in. Much easy. So it was this mechanical detail.

But !

This 7/8" brake cylinder ... The complete story is now coming out. It seems that the rods who press the pistons are of a longer lenght with the 7/8 cylinder. As are the return spring.
It seems also that in order to get enough press to declutch, I will have to shortern the retaining bar on the rear of the clutch pedal. This is there to prevent an excessive clutch pedal travel but now ...

After all it might be a better plan to try to rescue the original 3/4" cylinder. It was quite muddy inside after all these years, but thanks to the silicon fluid, I is not too badly pitted.
Spyros

I am sorry I could have told you that but longer rods are available at www.angloparts.com and work like a treat. I stumbled across this problem before.

Bas
Bas Timmermans

I rush to Angloparts show me back with 2 rods. Yes they are much longer. The salesman didn't believe me initialy, thinking that the parts catalogs were accurate. You can never trust them. Even Moss.
After some discussion, he finally look into a BMC part catalog, where 3 references are listed.

I left the plastic thing in. This because my 3/4" master cylinder has it also.
µ
And the brake and clucth bleeding is still not successfull. The Brake because one front bleeding niple doesn't want to be unscrewed. I didn't want to risk breaking it so I left it in penetrating oil and will go back tommorow evening with some heat.

The clutch slave cylinder is probably the only difficult part to get at. I startd the process but still to be worked on.
Spyros

Spyros, all your questions appear to have been addressed, good luck with the outcome.

WELCOME to this BBS, hope we'll hear from you more now. There is a thriving Spridget 'Familly' in Holland but you are (as far as I'm aware) the olny poster in Belgium. Will you be coming to 'Spridget 50' here in the UK?

Mark.
Mark Boldry

Hi Mark,

I'll join the BBS.
I'm a little surprised to be the only one of Belgium.
There are some Sprite over here. I cannot precise the number because I left the Belgian club some years ago.
The only thing I can say is that other than mine, there are only 4 others known HAN7 Sprites in Belgium. I believe I've still the only driving one.

It would be intersting to come to the Spridget 50 but I'm not sure this would be possible.

Back in 1995, I've also been a member of the MASC. (Quite remote, I'm affraid)

Regards
Spyros

Rather sh*ty day...

Yesterday evening, I quickly bleeded the clutch then went back to the front brakes.
The evening before, I noticed that the left bleed screw (my Sprite is coming from Arizona so also left driven) was stuck . So I had only bled the other side.
So, yesterday, I started by heating this screw then penetrating oil, then ... it snapped imediatelly ...
I was thinking that the rally was over ( my wife thinking the same had already cleaned our talbot; because one of my Bagheera (4 in total) was blocked in our one way garage by another one that has an oil leak I want to fix)
But then, I noticed another screw, next to the bleed screw. And ... something not to try.... I undid it pressed the brakes, screwed back ... brake pedal rock solid !!

Question : Can I just use this hole to fit another bleed screw ?

So this morning we went for the rally. 3 in the sprite (my 10 years old son didn't want to miss it)

Bas is correct, there is some (little) brakes binding. But nothing to stop our enthousiasm.

Until the first "draw the map" section. Midway this section, it became obvious that we had lost 1 cylinder.
Went to look. Nothing I though : one of these ebonit lucas terminal who was loose.
Well, just after completing the section, same issue but the engine staled.
Awfully hot coil !
So, verification of the distributor parts, seemed well , so I unscrewed the coil and gave it a bath to evacuate the heat (That was easy, we weren't short of rain today)
And now ? Should I stay or should I go home ?
We tried to continue but 10 km later, the ignition was completelly dead.
A good opportunity to renew everything.
And we started to wait the rally trailer. Of course, he missed the point and went to another city of about the same name . But finally he came to trail us to one of the rally stop and from there I had to organize my way home ...
S Mourelatos

Hi Spyros, sorry to hear about the rally.
I know how sh*tty it can be when braking down during a rally(1/2shaft broke during 12uur van Vlaanderen).
Im hoping to participate in Belgium rallys again later this year: 6uur van Noorderkempen en Gilbert Staepelaar.
I knew a belgium guy named Ronny with a orange midget who was invoved with the 6uur va N. organisation, you know him?

If you like rallies you probably dont mind doing some miles too so can i invite you to Holland for THE spridget-only Rally(toer&sport klasse) on the first of june in Tiel.
Or the 5th SpridgetWeekend on the 6&7th of September in Overdinkel(last year dutch, german and english spridgets).
I can send you more info if your intrested.
Arie de Best

Halfshaft broken ?

This : [img]http://img341.imageshack.us/img341/3048/dscn440110010nr.jpg[/img]

That was 3 years ago.
Now, both halfshaft are EN17 so it shouldn't happen again.

I don't know Ronny.
Let me know how far it is and I'll come if possible. So send me the infos.
Also you can come to one of the best Belgian rally were you don't need Halda : The "Rallye des Légendes" , each year this period and with 3 cathegories so that even the ones that are not used to these exercices can have fun.

The Sprite, in 2006 :
[img]http://img238.imageshack.us/img238/5852/dscn536616865zv.jpg[/img]

Yes, I know, the colour is not a Sprite one. It's supposed to be Pacific Green, a 63 Healey (big ones) colour. So it was period with the car and still related to the make. Altough I've been told that the paint shop must have done mistakes when mixing it
S Mourelatos

Sorry, I didn't know that the bbs didn't speak bbcode. To see the pictures, just remove the [/img] at the end of the url's
S Mourelatos

Spyros, That almost "Volvo Penta Green". But it is a nice colour on a very nice car. Could have been the sister of mine.

Bas
Bas Timmermans

Spyros, mail me at ariedebest@fishplanet.nl
remove the word fish.

Where abouts are you in Belgium?
Can you see Tiel en Overdinkel on your map of Holland?
Arie de Best

I know this is an old thread now. But I think using a 7/8" dual on older cars (besides the pushrod length) is only a problem if you've fitted a later gearbox. It's a clutch throw issue, not brakes.
Nick

Our frog has the healey disc conversion using the original master cylinder and has had no problems.....
David Brenchley

As Bas pointed, there is a slight disc brakes binding. I didn't got this with the 3/4" cylinder.
I blasted the 3/4" cylinder (microspheres) and it's going to receive sleeves.
Although, I'm wondering if for the clutch I will not simply rebore it to 7/8.
The clutch is working with my ribbed gearbox (original 10CG clutch system) and seems to have the clutch disengaging earlier (better)

Is there anybody who know if I can just use the calliper plug to fit a bleeding nut ? (see above)

Appart of this, there is still no ignition. I was thinking that it could be bad insolation of the little cable inside the ignitor, the one giving the contact to the coil. But even after rewelding it with proper plastic isolated cable, still no ignition. Will have to dig deeper.

I've also a question concerning the original 12G206 head that I still have somewhere, but this will be another post.
S Mourelatos

This thread was discussed between 14/04/2008 and 26/04/2008

MG Midget and Sprite Technical index

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