fusilier

The rally car is equiped with two Lockheed AP Racing 2293 Master Cylinders. They are rebuildable.

The rebuild kits are about 23 dollars each. And contain two new seals, boot, retaining ring and seal disks.

Disassembly of the cylinder requires some needlenose pliers and some Circlip pliers.
<img src="http://www.bufkinengineering.com/lockheed_mbc00.JPG">
Extremely straightforward and simple. Remove the circlip from the groove and the whole thing comes apart.
<img src="http://www.bufkinengineering.com/lockheed_mbc01.JPG">
The two seals are on the piston. The spring does not come in the rebuild kit so if that breaks the cylinder is pretty much a dead duck unless you get an equivalent spring. This older design cylinder uses that plastic seat on the end because the pressure exit line is on the end of the piston. More on this later.

<img src="http://www.bufkinengineering.com/lockheed_mbc03.JPG">

The rebuilt internals. I also went ahead and polished up the rod linkage and hit it with a clear coat to prevent surface rust.

<img src="http://www.bufkinengineering.com/lockheed_mbc04.JPG">
reassembled pistons. I do like the rebuild boots better than the original boots as then fit nicely in the shoulder cut on the linkages. These linkages are spun on a lathe and are definately AudiSport special parts as they are quite thicker and beefier than the linkages supplied by Lockheed.

<img src="http://www.bufkinengineering.com/lockheed_mbc05.JPG">
From the mounting face the center of the heim joint is about 7.5" from the mount face. This distance is adjustable depending upon where no the brake pedal you start the fulcrum point.

<img src="http://www.bufkinengineering.com/lockheed_mbc06.JPG">
And finally the superseeded new casting. I ordered two new CP2293 cylinders incase the insides of mine were scarred and not rebuildable. The website I ordered from actually shows the old CP2293 casting on their website, however, I got these. They are still 13/16" diameter internal piston size and use the same threaded hookups. 3/8"X24 on the outlet end (same as standard brake line) and 7/16"X20 on the inlet. The rally car is is fitted with a 3/8"X24 male to female steel adapter to protect the aluminum threads on the exit. The inlet is a 7/16"x20 banjo bolt to AN3. Basically a section of blue teflon hose with a hose clamp connects the inlet AN3 to the reserviour. Although AN fitted, they opted to use a hose clamp on a aeroquip hose.

So these new castings are CP6093. Push distance and everything else seems idential. It would even be possible to use the audisport rod linkages on these new castings the only difference would be a slight shift in the exit location. The new cylinders do not have a plastic bushing on the end of the spring as the exit is fed of the side of the cylinder instead of the end, There are some changes in the piston and spring, but the internal rebuild parts are the same.

Next step is some new 3/16 (4.75mm) brake line sections, fittings and washers to replace all the rusted and worn line ends.

squidix9

Next for me is the clutch MC. I'm losing it rapidly. That's the next project on the list. I just finished the last item on the list ahead of it so it's time to tackle this one now.

fusilier

To get the master cylinders?

squidix9

I'm taking every opportunity to stock up on whatever I think "might" go at some point or another.

fusilier

Truechoice has pictured the old style casting.
So I ordered, but they only have the new casting in 13/16" piston. All the hookups for the master cylinder is in English threads.
The brake line is 3/16" which is also 4.75mm.
Truechoice also has the rebuild kits as well as replacement reserviours and fittings.

Just one of those things on the rally car that is in English threads like the AN stuff.<ul><li><a href="http://www.truechoice.com/prodinfo.asp?number=CP%202293">http://www.truechoice.com/prodinfo.asp?number=CP%202293</a</li></ul>

squidix9

Thanks, I'll order a pair

fusilier

The inner cylinder on mine looked pretty good and I think the rubber wears out long before the steel piston makes contact with the aluminum cylinder walls.

squidix9

Thanks for you help