Girling / PBR replacement master cylinder? (rebuild kit)

[LotusEngineeringBuff]

Dear All,
From the bills I have the previous owner of my plus2 S130 fitted a tandem master cylinder he sourced from "the Elan Factory" close to Melbourne. BTY I was not able to get the phone line to ring when I tried calling this morning.

I strongly suspect there is something fishy with this master cylinder and I am trying to get a rebuild kit. I was able to read the stamping on the core. So now I know I have a M/C

PBR of type E4C 5D, nice!

But I have spent a couple of hours on the Internet (at least) and have found nowhere a place that sells this M/C or a rebuild kit for it. Neither have I found any information on the compatibility between the original M/C (Girling 64063876) and the PBR one and therefore I do not know if I can order the Girling rebuild kit

It would be a shame to have to discard this almost new and expensive M/C because of the lack of rebuit kit.

Can anyone help? Many thanks in advance

Fran?ois

[richardcox_lotus]

Found this link. As Elan factory is Australian, I'ts probably a good start.

http://www.pedders.com.au/kits/pbr-miscellaneous-brake-products

[rgh0]

PBR are a large Australian brake manufacturing company who have supplied manufacturers such as Ford GM and Toyota here in Australia and world wide. The make a range of replacement components from other manufacturers including Girling

The PBR master cylinder should be able to use a Girling equivalent rebuild kit I believe but you would need to do a careful comparison to ensure this is correct. The alternative wold be to get a PBR rebuild kit from the Elan factory

cheers
Rohan

[2cams70]

I'm assuming you are attempting to rebuild the master cylinder in the hope that it will eliminate the excessive travel problem. Is the excessive pedal travel problem something the car has always had or something that has developed over time? If it is something that the car has always had (i.e since the replacement PBR cylinder was fitted) the problem is more likely to be incorrect master cylinder sizing, as another poster said, rather than an internal fault within the cylinder itself.

PBR master cylinders are generic designs. The one supplied to fit the Lotus probably also fits something much more mundane. With the help of a picture and cylinder diameter information it may be possible to more easily find parts for it if we can find a more common vehicle it may be fitted to. I'm not sure whether PBR still exists given the current state of the Australian automotive industry but up until recently they did publish quite detailed product catalogues and it may be possible to cross reference from them. It may also be possible to find the same generic master cylinder design but with a different cylinder bore diameter that better suits. It will be tricky and some experimentation will be required to correctly match the competing factors - master cylinder boost ratio, servo boost ratio, pedal effort and pedal travel.

Don't forget to check the servos either if they are the hydraulic type ! (I had this problem with similar symptoms on my Escort which has single circuit master cylinder and Girling hydraulic servo). You may also be better able to isolate the cause if you block off each half of the split circuit in turn and see what effect it has.

[LotusEngineeringBuff]

Found this link. As Elan factory is Australian, I'ts probably a good start.

http://www.pedders.com.au/kits/pbr-miscellaneous-brake-products

After some research I found that The Elan Factory is now Lotus Marques. Same address, same phone number, same Steve! I am happy to be in contact with him and he's going to find a rebuild kit for me.

Once I have it, I'll be able to tell if its compatible with the original Girling rebuild kit. Maybe it WILL be the Girling kit!

[denicholls2]

There are at least two different bores commonly used on Lotus master cylinders of the period. The larger bore is intended for use with boosted systems as it has a higher pedal effort and lower pedal travel to move a fixed amount of brake fluid down the pipes.

The smaller bore is intended for use with unboosted systems. It has a longer pedal travel and lower pedal effort to achieve the same fluid displacement.

There is general agreement that the cylinder designed for boosted systems does not have sufficiently high pedal effort to prevent its use in unboosted applications. Some owners prefer the firm pedal and are willing to push harder to get it.

I'd suggest before you replace relatively new seals that you test the device. If the pedal has more motion than you like but does not drop to the floor with a constant pressure applied, it is likely a smaller bore unit working properly. Buying new seals for it won't change its mechanical characteristics.

I would expect the replacement unit to work properly with the correct seal kit for the bore diameter, though maybe not. In any event, you'll have to start with the bore diameter to get new seals if you want them to fit.

[denicholls2]

One more thing: If you do choose to swap a small bore with a large bore unit, you need to make sure that the fiberglass of the firewall where the unit mounts is in good enough condition to take the extra pedal effort. This has been identified as a potential safety problem due to Colin adding a bit too much lightness for 50+ year old plastic bodies to support design modifications.