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MK1 Brake Servo Rebuild (parts and tool)
Posted: Sun Sep 06, 2020 2:06 am
by green1071
Maybe well known information? / FYI / And some questions...
I have been running a 'Bentitialia' part number L7Q Brake Servo on my 64 mini cooper s. It looks identical, but is an alloy casting instead of iron. And different part numbers.
It recently failed - Unlike my original brake servo which has a pitted bore this one was clean and re-buildable by me. The Lockheed Rebuild instructions are posted in Technical part of MK1 - Thanks Mark!
I bought a OKP repair kit from
www.classicalfa.com. But to rebuild the unit you need a special tool per Lockheed Rebuild instructions to insert rubber seals. It is a sleeve so you can insert the smaller inner seal into smaller inner bore.
Questions:
1. Is this sleeve tool sold anywhere?
2. What is the seal life expectancy of the brake servos? I am running a silicon base brake fluid.
tool resize.JPG
Re: MK1 Brake Servo Rebuild (parts and tool)
Posted: Sun Sep 06, 2020 3:42 am
by cmiller
I don't know if this assembly tool is available. The factory workshop manual has the dimensions for it and if you have a lathe it is easily turned. I made one many years ago and it is invaluable to put the servo back together. Perhaps a friendly machinist in your area could help you out.
Chris Miller
Re: MK1 Brake Servo Rebuild (parts and tool)
Posted: Sun Sep 06, 2020 4:22 am
by LarryLebel
A bit off topic but if you're using silicon brake fluid I recommend the Harley Davidson hydraulic switch. I've been using one without problems for a couple of years now where previous generic ones lasted only a few months. The p/n I have is 72023-51E. My local Harley dealer has written 2E15 on the package.
Re: MK1 Brake Servo Rebuild (parts and tool)
Posted: Sun Sep 06, 2020 12:04 pm
by InnoCooperExport
I've been putting off rebuilding my Bonaldi servo (same as Benditalia, same as mk1 Lockheed) for a while now, thanks for the heads-up on the service manual! I'd been using the diagram in an earlier WSM I have which doesn't describe the tool you mention. Would be good to find one but also a good excuse to dust off the Myford...
Re: MK1 Brake Servo Rebuild (parts and tool)
Posted: Sun Sep 06, 2020 9:37 pm
by green1071
Thanks all for the information.
Chris M - I had a local machinist make me one. He asked if I wanted a batch of them made if anyone is interested in one. Cost would depend on quantity. I did notice that the Lockheed just calls out for a straight OD cylinder. While actual use on the 'Bentitialia' has to have a outside diameter step in it. You can notice in picture.
Larry thanks for HD part number. Original switch still in mini, but should get a spare.
InnoCooperExport you will also need to make a small tool 5/16" brass rod to hold down inner spring parts to install circlip. See picture. Tool should is bent for repairing my old MOPAR rear main oil seal when in car, but worked great. The bend in tool does help getting a needle nose to squeeze circlip.
Re: MK1 Brake Servo Rebuild (parts and tool)
Posted: Sun Sep 27, 2020 7:56 pm
by edwardg_smith
green1071 wrote: ↑Sun Sep 06, 2020 2:06 am
Maybe well known information? / FYI / And some questions...
I have been running a 'Bentitialia' part number L7Q Brake Servo on my 64 mini cooper s. It looks identical, but is an alloy casting instead of iron. And different part numbers.
It recently failed - Unlike my original brake servo which has a pitted bore this one was clean and re-buildable by me. The Lockheed Rebuild instructions are posted in Technical part of MK1 - Thanks Mark!
I bought a OKP repair kit from
www.classicalfa.com. But to rebuild the unit you need a special tool per Lockheed Rebuild instructions to insert rubber seals. It is a sleeve so you can insert the smaller inner seal into smaller inner bore.
Questions:
1. Is this sleeve tool sold anywhere?
2. What is the seal life expectancy of the brake servos? I am running a silicon base brake fluid.
tool resize.JPG
Hi Green1071,
Do you know if the ClassicAlfa BR006 Bendix Brake Servo Kit (Which I assume you used?) also fits the AP Lockheed (Original) type in the Mk1 Cooper S'?
I need to rebuild mine and can't find a kit.
Thanks in Advance,
Ed
Re: MK1 Brake Servo Rebuild (parts and tool)
Posted: Mon Sep 28, 2020 4:21 am
by green1071
Ed:
I used the ClassicAlfa BR006 Bendix Brake Servo Kit, which is for a 5/8 slave cylinder bore. Per the Lockheed Rebuild instructions there are 4 slave cylinder bores 5/8, 11/16, 3/4, and 7/8. And matrix shows original Lockheed part numbers. More info here:
http://www.bobine.nl/turner/06-front-su ... ake-servo/
I cannot remember what bore my original was/is. I took it apart and put it back together and can not find the data I wrote down. I am pretty sure it was 5/8 bore.
Thus if you measure your slave cylinder diameter, smaller inner one. You will know which kit to find.
You will need a sleeve to install inner seal and rod to hold everything compressed while you install spring clip.
james
Re: MK1 Brake Servo Rebuild (parts and tool)
Posted: Tue Sep 29, 2020 8:33 pm
by edwardg_smith
green1071,
Ideal info. Thank you very much indeed. I'll have a measure up!
All the Best,
Ed
Re: MK1 Brake Servo Rebuild (parts and tool)
Posted: Tue Sep 29, 2020 8:56 pm
by edwardg_smith
Another quick question if I may? having taken apart my servo, which appears to look identical to the repro as supplied by Mini Spares, I have discovered I am missing the Spring Guide and the Spring Retainer from inside the slave cylinder (Bottom and top of spring) ??? Is this normal of reproduction units or is this wrong?
Thanks in Advance Everyone!
Ed
Re: MK1 Brake Servo Rebuild (parts and tool)
Posted: Wed Sep 30, 2020 2:18 am
by green1071
Ed,
Here is a picture of my Italian brake servo parts minus vacuum booster / chamber.
My original Lockheed had same parts.
Mark has Lockheed service manual in Technical section which I referenced.
http://mk1-performance-conversions.co.u ... anical.htm
james