Hydraulic throwout bearing, Has anyone sized one for the 901 trans? Options

[groot]

I'm fed up with my hydraulic slave cylinder. I wish I stayed with the cable actuation, but I can't go back now.

I know I could drop a mint getting a custom job, but I was hoping someone had done some homework to figure out if one of the Howe cylinders (or competitors) will fit and function for the 901....

Howe Racing Parts-Throwout Bearings

[ClayPerrine]

Contact Rich Johnson. He has a kit for the 914 to install a hudraulic clutch. He can point you in the correct direction with concerns about the slave cylinder.

Rich's e-mail a914guy@aol.com

[TimT]

wevo makes one that bolts right in a 901 box, mucho dinero

Tilton also makes hydraulic t/o bearing, but they will take a bit of fitting to make work, not as much dinero

[914efi]

I've put them into other cars, it usually requires some spacers and maybe a sleeve for the input shaft dependin on size, but it's not a big deal. I bought a Howe from a race supplier for ~$100.00.

[groot]

Thanks. That's what I was hoping to hear. I'm not into dropping $800 for WEVO, when there are other options out there.

[Brett W]

What's the problem with the slave cylinder style unit you have? I was planning on using that type on my race car.

[groot]

Long story, but I'll abreviate...

So, I put a pull-type slave cylinder in the position where the cable pulls, which runs very close to my header... too close. I also didn't feel like I was getting enough throw to fully disengage the clutch. That didn't work.

Next I built a linkage that uses a bellcrank so I could mount the slave cylinder up and further away from the heat and amplify the motion. Now the fluid doesn't get too hot, but the linkage is binding up, so the efforts are too high and more than once, I've lost the ability to actuate the clutch during a race.

I could rethink my linkage, but I'm just creating a complex system that could be much simpler. Simplicity is the best answer, so, I'm going down this other path.

[airsix]

Kevin,
the CNC/Wilwood slave cyl has more than enough throw. If you're not getting enough travel it's because your' Master-cyl bore it too small. The papers that came with the slave cyl include a recommended MC bore size. Get rid of the bellcrank stuff and make a heat shield to keep the heat away. If mine can survive being shielded and just inches from my turbo I'm sure you can shield yours from the header. Hope that's helpful. (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)

Another tip - since the slave is actually higher than the MC I put a 2psi check valve in the line at the MC end. Prevents soggy peddal when the car sits for a while. You can get the right valve from Wilwood (disk brake anti-drain-back valve).

-Ben M.

[groot]

Interesting. How close is your slave cylinder to your turbo?

I even shielded my slave cylinder and the fluid still turned black after one session on track. I'll look at it again, maybe I can get a bit more clearance and upsize my master cylinder.

[groot]

I'm running a Triad West header.

In the picture from Triad Dave's website, you can see why I have a heat problem. This is not my car pictured, but you can imagine if there was a slave cylinder in the space where the clutch cable bracket is how little clearance I have. I don't think I'd have a problem on the street, but during a race the header does get a bit hot.

[airsix]

Wow. That triad header is right on top of your slave cyl alright. I didnt' realize it was the collector camped out right on top of it. I figured you had one pipe that was close. Now I get it. Your collector is much closer than my turbo. You could ceramic coat the header (or wrap it). I bet that would help a bunch.

-Ben M.

[Thorshammer]

Kevin,

You can't beat the Saab 900 hydraulic slave. I buy my from Taylor race at about 70.00 their cheap. You will need to Build a piece that presses into the 901 where the seal goes, and teylor sells a smaller input shaft seal. I basically spun up a piece of aluminum that would hold the smaller seal, and then countersunk the bolts to hold it to the trans, next I attached the Saab slave to the adaptor using three allen bolts. The saab slave has a small lip on the trans side to center the unit. So you won't have to worry about another tube to center the cylinder. like an old VW type 1. Make sure you seal the adaptor to the trans with something that it okay with gearlube ie.. silicone.

You should have the room you need. AP lockheed has the saab cylinder specs online. I did the install in the Hewland, in this same manner, but installed height was very tight for me, I would build a custom unit if I did it again. and use the Saab piston. Most everyone in FC/Atlantic uses this saab slave, rebuild it yearly and it will never fail you. I use a 5/8 master cylinder to actuate it. I got my original set up from RIC racing of Bow NH, Rick is very sharp with this stuff. I have pics, just can't find them right now.

Erik Madsen

[groot]

Very nice, Eric. That sounds ideal. Pics would help alot, if you can find them.

Sounds like this adapter takes the place of the old throwout bearing guide tube?

BTW... are you using a single plate clutch?