Brake master cylinder

[ailwyn]

If anyone is desperate and can't get one, I'll order again from the same place and post it on, but it will then end up costing you more that it should.

[paza1]

Sorted through a different branch...absolutely no problem this time Price was £83 & VAT. Pick up tomorrow. Thanks to all for info.

PS Are they difficult to replace? The Manual makes it sound easy...

Cheers
Mark

[ailwyn]

The Manual makes it sound easy...

I managed to do this, with a lot of cursing, burning rage (on several occasions), and plenty of time.

Someone more seasoned would have done it a lot quicker.

In order to do mine I needed to buy a set of metric crow's feet as access to the inboard mounting nut for the master cylinder is impossible without them. I also had lots of fun trying to remove the brake lines from the old cylinder.

Refitting was also a barrel of laughs mainly due to the restricted access.

Check your brake lines that come from the master cylinder, if there are signs of corrosion (particularly where the brake pipe meets the brake hose at the wheel arch liner) then get them replaced while your doing the job, it's easy enough and it'll save you messing with the master cylinder again.

[surfboardfiller]

I paid someone else to do it

Also a good opportunity to fit braided hoses if you haven't already.

[paza1]

Ailwyn,
Good advice about replacing the lines ( have fitted stainless flexible hoses and new solid lines all round ).
I assume that MC butts up to the servo with a seal and an arm of some description goes into the MC from the servo?

Phil,
Agreed... Stainless hoses already fitted. I have mine booked in for repair but am curious about others experiences.

Cheers
Mark

[ailwyn]

Mark,

Have a look at this pic from Monty which shows the rear of the MC.

There is a pin (as best I can describe it) about an inch long, which is pushed out by the servo into the MC.

Basically, remove all 4 brake lines, remove the two retaining nuts, then MC & reservoir slide out.... bet that's how it's written in the manual too

While your at it you may as well get a new reservoir, they were on the Lotus surplus list for, I think, £20 delivered.

[surfboardfiller]

Mark,

Have a look at this pic from Monty which shows the rear of the MC.

There is a pin (as best I can describe it) about an inch long, which is pushed out by the servo into the MC.

Basically, remove all 4 brake lines, remove the two retaining nuts, then MC & reservoir slide out.... bet that's how it's written in the manual too

While your at it you may as well get a new reservoir, they were on the Lotus surplus list for, I think, £20 delivered.

It was £8 but you managed to pay £18, I wouldn't mind but you bought me one for £18 too! I guess they ran out of the cheap ones

[ailwyn]

I think it was something like £14 + £5 postage + vat. Came in at £18 because we effectively split the postage.

Order your own in future

[paza1]

Is there a seal between the MC and the servo body (not the piston seal)? If so, what size and where can I get one? Just weighing up what I/the mechanic will need.
Cheers
Mark

[ailwyn]

Mark,

I didn't come across any seal, as far as I'm aware any seals are built into the MC.

I couldn't say that there was no seal on the servo side, but I didn't replace it if there was.

Ailwyn

[surfboardfiller]

I think it was something like £14 + £5 postage + vat. Came in at £18 because we effectively split the postage.

Order your own in future

[Candles]

Off the list above found this one on the US ebay

I bought it, and it was the right one. Thanks Monty!

[Monty]

Off the list above found this one on the US ebay

I bought it, and it was the right one. Thanks Monty!

Oh you



Thats good news, and do the pipe fixing match up?

and was it cast iron? as the stock one is alloy

[Candles]

Alloy and the holes line up but I haven't tried to screw anything in yet. Ooh err: the brake unions I mean!

[Monty]

Ok, i just picked up the new BMC from the post office which i won of ebay and came from the USA, cost me less than £20 including postage Think Candles has the same one.

But there`s a problem for the brake pipes, the two upper connection holes are correct but the two lower are huge and the brake pipes do not fit maybe it`s possible to find an adaptor The good news is that the inners should be the same and could be swapped over to the stock BMC.

This is the one i won

Pontiac LeMans VL 1990-93 Brake Master Cylinder
NEW IN BOX........BECK / ARNLEY...Part #072-8751 This BRAKE Master Cylinder is new....MADE IN U.S.A

The one i`ve got is also listed on RockAutos

BECK/ARNLEY Part # 0728751
2631 Stamped On Top Of Brake Booster [Wholesaler Closeout -- 30 Day Warranty] $88.99

[ailwyn]

maybe it's possible to find an adaptor

The fronts and rear lines have different connectors, I think the fronts are the larger ones on our setup, which IIRC are the upper connectors on the BMC.

Are you saying that the lower connectors on your new BMC are larger than the pipe fittings (but the same as the uppers) or are they larger than the uppers?

If the latter then I don't know what to suggest, if they are the same fitting as the upper then you could do two new pipes for the rears, using the stock female fitting (there is a join right behind the centre of the plenum) and get some of the larger (13mm?) male fittings to connect to the BMC.

Hope that makes sense

A.

[dapinky]

(there is a join right behind the centre of the plenum) and get some of the larger (13mm?) male fittings to connect to the BMC.

Hope that makes sense

A.

Makes sense to me!

All I would say (AND I'M PROBABLY WRONG) is that as it is from a USA vehicle, the other (larger) holes may be an imperial 1/2" as opposed to a metric 13mm.

Either way, GET THE CORRECT FITTINGS - NOT JUST SOMETHING THAT 'FITS'.

I know you will do it right, anyway - but i don't want anyone to assume anything when it comes to brake systems.

[Monty]

It`s easyer to show a Picture, i used the old brake pipes from pinky1 to test the connections.
I`ve measure the lower thread hole with digital calipers and getting 13.99mm so thats looking like a 15mm connection

BTW, i`m not actually fitting the BMC yet, i`ll do that when i end up doing the HG again

[Candles]

Right, I'm in the same boat as Monty above, however I want to get it sorted soon. Possible ways around it:

1) Procure the correct fitting and flare-up some pipes to go between the MC and the rear brake line connector which is behind the plenum.

2) Replace original MC's internals with the new ones. But what if the bore is scored or worn?

I'd go down either route here if I could get the old one off! I cannot get to the pipes to undo them, nor can I undo the nearside mounting nut! I've got the arch liner out so the offside nut was a piece of old wee, but I'm stumped with the rest! I'm almost tempted to just cut through the pipes and make new ones for the reinstall!

Anyone got any solutions more practical than 'grow Golum arms!'

Also, can I just pull the reservoir off?

Candles.

[Monty]

They are big connections must be some kind of reducer out there

If not i`d think i`g go for swapping the Inners, can`t see the bore being scored and all this talk of not pressing the brake pedal all the way to the floor when bleeding the brakes is all tosh as Pinky1`s old BMC look`s like new ie no crud or corrosion on the inside.

Not sure about your Nuts ( ) but i didn`t have any problems removing the old brake pipes from pinky1`s BMC. If you end up cutting them off then it would be worth making new pipes to match the your new BMC.