Brake master cylinder

[ESM]

I think its AC Delco part no xxx-xxx (standard) or xxxxxx (durastop). <br><br>

Read to the end of the thread for more reliable info

[Sy V]

Aah<br><br>Based on the fact that...?

[ESM]

It looks the same, its got the same piston size and, like the calipers, it comes from the Pontiac LeMans GSE.<br><br>

[Doug]

if someone sent an email to Lotus HQ to inquire about this, would they answer and confirm it ? ? ?  ::)

[Sy V]

I was hoping you were going to say that you had received a replacement Alan...

[ESM]

I'm 95% sure its the right part number. I've also come across a fixture compatible part with a 24mm piston (stock is 22.22mm) that might be of interest to the people with big brake upgrades. Its a xxx-xxx (standard) xxMxxx (Durastop).

I've asked Chris Foulds about price of the 22.2mm piston part but I'm not optimistic that it'll be cheap. The one US web site that had a compatible Delco part (a Durastop) was listing it for more than $300... The Delco site lists the Le Mans as the only car this was fitted to so its probably not the most common bit around, unless it found an application in a European car that we haven't established yet. I did find a site that listed an equivalent from an aftermarket source for $80 but I rather stick to the original manufacturer.

Read to end of the thread for more reliable part nos

[lotuska]

Can confirm that the brake master cylinder is made by AC Delco as I replaced mine a couple of years ago. Got it from a vauxhaul dealer part number 3492616, hope that helps.

[Sy V]

Do you happen to remember roughly what you paid for it please?<br><br>http://www.lpr.it/idraulicaorg.asp?org=3492616<br><br>Italian, but appears to fit a GM Opel car.<br><br>English version<br><br>http://www.lpr.it/eng/idraulicaorg.asp?org=3492616<br><br>With an LPR equivalent part...

[lotuska]

From memory I think it was about the £100 mark (it was at least 4 years ago), which even then was significantly less than Lotus wanted (a friendly part manger also gave it to me at trade), I remember passing the details onto PMatty.<br><br>And looking at what you've found I do remember that there were differences between the ABS and non-ABS version fitted to the Vectra and it definitely was from the 2.0L version. I think the other types had different mountings.<br><br>I also remember that there were a series of numbers stamped into the cylinder which were only easiyl visible when removed from the car. Again I think they were on the top under the reservior.

[BigErch]

Just replaced my master cylinder - what a difference! I now have brakes

I tried the Vauxhall number above but the dealers wanted £160 + vat.
My local motor factor cross referenced this number with LUCAS parts and came up with "PMH 392". Cost £100 + vat and fits perfectly. You have to use your old reservoir.

Hope this helps, Arch

[Sy V]

Great work Arch.

Can you outline the improvements against your old unit please?

I note your "I now have brakes" statement, but what are the improved symptoms?
Pedal feel?
Pedal travel?
Braking efficiency?
Bleedability (good made up word!)
Wheels lockability even?

[Monty]

Thats great, at least thats another part we don`t have to rely on Lotus for LOL.

Since my front brake upgrade, i`ve got a soft pedal (the brakes work great) still needs another bleed. But wonder if changing the master cylinder will be the next step some time in the future.

Big Erch

was it a big job to fit?

[BigErch]

Great work Arch.

Can you outline the improvements against your old unit please?

I note your "I now have brakes" statement, but what are the improved symptoms?
Pedal feel?
Pedal travel?
Braking efficiency?
Bleedability (good made up word!)
Wheels lockability even?

Hi Sy,

Ever since I got the car the brake pedal has been uninspiring.
The Pedal was always nearly to the floor before starting to firm up (still slightly spongey tho). Even then the braking performance was poor and sometimes frightening . Bleeding the system helped but only in the short term.
Firstly I overhauled the existing calipers but that didn't help much. Then I fitted a HiSpec kit and the pedal travel became worse (more volume in the 4 pots i guess). Finally I've replaced the master cylinder. The old one looked like it had a small leak at the union with the servo which probably didn't help. I'd never spotted the fluid level droping but maybe air and moisture was getting in.
The pedal travel is perfect now and progressively firms up nicely. I haven't locked the wheels yet but I'm sure i could.
I've always compared my brakes to Stevos Missy and finally they are nearly on a par. I think the difference is his 285 discs compared with my 275 which fit behind my little wheels. Sometimes size is everything but I'm very happy with what I've got

cheers, Arch

[Sy V]

Exactly what I wanted to hear mate, thanks, great.

Now on to Jay's question...was the fitting particularly arduous?

Sy

[BigErch]

was it a big job to fit?

Hi Monty,

It's one of these jobs that require small dexterous hands.
I unfortunately have not been gifted with such appendages so I had to employ a small mechanic friend to do the job. It took him and hour to get the old one out and he said it wasn't easy.

If your suspicious of the pedal throw or the softness of the brakes then it's well worth replacing this component. I can't believe I've put up with crap brakes for nearly a whole year.

cheers, Arch

[lotuska]

Again from memory access to the brake master cylinder is much easier through the wheel arch, take the liner out and you shoud then be able to see the master cylinder and all bolts.

[ESM]

Sy's Italian site pretty much sorted out all the part numbers and applications

Applications
Part Nos

I reckon we now need to find a reasonably priced compatible part with a bigger piston.

With regard to replacing it, access isn't too bad when the power steering reservoir is removed. Be careful where fluid goes during removal, I think I lost an alternator because fluid got into it during a master cylinder change.

[kmckmc]

http://www.rockauto.com/catalog/catalog ... ttype=1836

This place has Durastop Master Brake Cylinder at around 250usd

[surfboardfiller]

I am despirately trying to find a replacement Cylider and pipe, I gave the supplier the part numbers for the Lucas but he said there should be a number stamped on the cylinder.

Does any one have this number or tell me exactly where to find it please.

Thanks,

Phil

90 SE

[GeoffSmith]

WillB's flogging one on FleaBay.