Clutch Master /Slave Problem

Jon Miller · #1 (**permalink**) 09-13-2006, 06:21 PM

Well, after 10 years it finally runs. Now if I could just get it drivable.....

I can't get enough stroke to disengage the clutch....I've got a 3/4" Wilwood compact master cylinder(the largest they build), and a late 50's stock Ford truck slave cylinder. The slave looks like it has a 1" bore. What I need is a 3/4" bore slave. I've got a lathe and I've been thinking that maybe I could sleeve it down to 3/4, but that would probably be a big waste of time since it would most likely leak like crazy.........

Does anyone know of a 3/4 inch bore PUSH style slave cylinder that can be adapted to work on a Cobra with an FE? ERA uses a BMW part, but it's "Special Order" at the local parts store, and I can't find any specs on it. I don't want another $100 paper weight!

Thanks,
Jon

pgermond · #2 (**permalink**) 09-13-2006, 07:06 PM

NAPA, part#33721, 1" bore, $55. I have the Wilwood 3/4" m/c mated with this slave.

http://www.napaonline.com/MasterPage...Slave+Cylinder

fastrods · #3 (**permalink**) 09-13-2006, 07:59 PM

Speedway motors has a 7/8" push style for $49.95, part #91025605. I used it with the Wilwood master.
http://www.speedwaymotors.com/xq/asp...qx/Product.htm

bobt427 · #4 (**permalink**) 09-13-2006, 08:54 PM

I have the same clutch slave as you 1" bore. I use to have a 7/8" master,but now just switch to a 1" willwood master with remote reservoir.It works very well. I have the wilwood 6 to 1 pedal ratio flour mount setup.

Jon Miller · #5 (**permalink**) 09-13-2006, 10:05 PM

Thanks Guys,
The only master that will work with my Super Custom Home Made Frame/Floor Mount Pedal Assembly is Wilwood's compact master which does not come any bigger than 3/4". I only get 1" travel at the master, and as I understand it, I need 1" travel at the slave to get things to work right. A quick check of the physics of things leads me to believe that I can only get this done with a 3/4", or smaller slave.

The 7/8" may work.....or I may end up with another high dollar paper wieght.

I can bump up the travel at the master to a max of 1.44", but that would not be much fun.....Think lots of cutting and welding followed by much brake bleeding.

Thanks,
Jon

bobt427 · #6 (**permalink**) 09-13-2006, 10:47 PM

With the 7/8" master I had barely moved the slave fare enough to relase the clutch. The 1" master is the one you want. Wilwood part#260-3378 this one comes in a kit with the resivors. It will bolt up the same as the master you already have.
I don't no if you no ,but the 1959 ford truck that uses the slave has 1-1/8" master.

Jon Miller · #7 (**permalink**) 09-14-2006, 08:47 AM

The Wilwood COMPACT master only goes up to 3/4". It's not the same as their REMOTE master, available in bigger bores, which is too long to fit in my car......

I could not get a good measurement on my slave, but if it is 1 1/8" then just maybe the 7/8" slave would work if I increase the stroke of the master(see "cutting and welding" above)....time for a little math.

Does anybody know what the bore of the BMW slave that ERA uses is?

Thanks!
Jon

John Annie · #8 (**permalink**) 09-14-2006, 09:53 AM

Jon,
This may get you started as you'll probably have to contact a BMW parts department for additional information. But my ERA manual lists the following BMW part numbers:
Clutch master cyl.(Fits 72-76 2002)BMW 1252 1104 510 or Tilton 74-875 (special)

Clutch slave cylinder: BMW 21521104269

Hope this helps.

The more I get into building my car the more impressed I am with ERA and the excellent job they've done with the car and their manual. Thanks Bob!!

John Annie

Jon Miller · #9 (**permalink**) 09-14-2006, 01:24 PM

The best single purchase I made during the construction of my Everett-Morrison was the manual from ERA....

Thanks,
Jon

The Dreamer · #10 (**permalink**) 09-14-2006, 02:24 PM

I had the same problem as you. I had my slave resleeved to .75" by White Post Restorations. They are expensive, but guarantee the slave for life. My set up works great, so I'm happy.

pgermond · #11 (**permalink**) 09-14-2006, 05:31 PM

Quote:

Originally Posted by Jon Miller

The best single purchase I made during the construction of my Everett-Morrison was the manual from ERA....

Thanks,
Jon

Yep, me too - when I built my Unique.

SantaFe66 · #12 (**permalink**) 09-14-2006, 06:46 PM

Have you looked at Tilton? www.tiltonracing.com

I have their top hung setup and after finding that my Tilton Hydraulic T/O bearing needed replacing, I ended up also replacing the master cylinder so the two matched. The clutch works flawlessly now. I didn't think I would like the hyd. T/O but my mechanic has one in his racing stock car and has had zero problems with them leaking. They have many options for master/slave setups. Go to their website and poke around. Make sure the master matches what they recommend to go with the slave bore diameter you have. Their tech people are real helpful too.

Good luck.

Paul

Jon Miller · #13 (**permalink**) 09-14-2006, 07:34 PM

Since I Realllly want to get this thing on the road, it will be ten years at the end of the month........I spent a half hour at the local parts store with a dial calipers in hand, and ended up with a Raybestos SC360018. My donor list has now expanded to include Mazda, 1993 MX-6 to be exact. I built a new bracket this afternoon, and if I can get a 10mm to AN4 adaptor locally I'll be driving the Cobra Friday after work!

Thanks for all of the help!!
Jon

Michael C Henry · #14 (**permalink**) 09-14-2006, 09:13 PM

My car had a 7/8" dia Tilton master cylinder and the slave cylinder travel was so limited that either I could get full release or some free travel. Once It took out my clutch forks when the throw out bearing failed. I converted to a 15/16" dia master Tilton cylinder , and it worked great. Just a little more volume and a little less leverage. full clutch release and free travel.

armandjones82 · #15 (**permalink**) 08-04-2010, 07:53 PM

I know that this forum thread has been old enough to be replied on, but I must say that reading this specific post about Clutch Kit change or master/slave problem was a good read. You must be able to really understood well the things that have been mentioned here and continue to really amaze on how things work. Great post indeed! Thanks for this one!