McLeod Internal Hydraulic Throwout Bearing with NP435

[86Horn_EB_77]

Is anybody running a McLeod Internal hydraulic Throwout bearing with their NP435?

I have the driveline installed and I'm ready to hang the 3/4 inch Wilwood clutch master cylinder on the firewall. All the installs I've seen use the Speedo cable hole in the firewall. That looks like it would put the master cylinder pushrod about 3 inches from the clutch pedal pivot. The McLeod instuctions say the master should be 2 inches from the pivot.

Moving the master up will be a pain because you run into the brake master cylinder angle bracket on the firewall.

Is anyone running this setup? Where did you locate your clutch master cylinder and how do you like the pedal force? Are you running a 3/4 inch cylinder?

thx

Jim

 

[86Horn_EB_77]

Anybody?

So nobody is running a McLeod on a 435?

Ok - different question. How many are running ANY internal hydro throw-out bearing setup with a master cylinder mounted at the speedo cable hole?

Are you using a 3/4 inch master and what's the pedal effort/travel feel like?

thanks

Jim

 

[Dbteak]

I have a McLeod on my mustang and it is a very hard pedal. I moved the hole up on the pedal as far as I could and still get the travel and keeping the pushrod strait. I originally had a larger MC and swapped it out to a 3/4. It is still stiff. I found these http://www.moderndriveline.com/catalog/hydraulics.htm at Hot August Nights. I am planning on swapping it out for one of them. They just need to know what throwout bearing you are using. I know it is not for a bronco but it may work if you need to lower the MC.

Doug

 

[mavereq]

i'm using a wilwood master and an angle bracket for the brakes. i had to notch the brake bracket to mount the clutch master up higher. i plated that whole section of the firewall with 3/16" to make it more rigid. i definitely wouldn't go any further below the pivot as that would make the clutch more stiff and harder to manipulate. i'm considering dropping down to a smaller master for a lighter pedal. i have a 3/4" now.

 

[phred]

I've got an external slave cylinder and fire wall mounted master. I looked at going with the internal release bearing but the front cover on the 435 has to be modified, at least according to Tillton engineering. The release bearing housing is fixed solid to the front cover and bearing then moves back and forth along the snout of the input shaft. Parts alone to covert my 435 to use an internal release bearing was close to $1000 plus machine work. I opted for the external slave. Easier to adjust and if it leaks I dont have to pull that heavy tranny to replace it.
The clutch effort is fairly heavy with the hydraulic setup but the breakpoint of the pedal is consistant and smooth. The master is mounted beside the brake master. I welded a stud to the clutch pedal, similar to the brake pedal, to actuate the clutch push rod.

 

[patterdale]

I'm not running it on my 70 because it is all stock but had one on my 94 f-150. I was wondering if there are problems with them in extreme heat since you are from Texas. I know here in MInnesota we had big trouble with them blowing out seals in extreme cold. I changed 3 of them over the time I had the truck laying on my back on the garage apron in the winter. In my opinion it was not one of Ford's "better Ideas".

 

[86Horn_EB_77]

Thanks

Thanks Guys - I appreciate the input.

I bought this McLeod setup from a guy that had it custom engineered for a 435. You basically unbolt the front bearing housing from the 435 and replace it with a new housing that has the slave piston and bearing built into it. I double checked the bell housing to trans face dimensions and everything was good to McLeods instructions.

I think my first shot will be to change the Master to a 5/8 bore if the pedal is too hard and/or see how much I have to mod the brake master angle bracket to move the clutch master cylinder & rod higher on the firewall and pedal.

If all that doesn't work, I guess I can drop the big bucks on the modern driveline master & linkage.

Dbteak - do you have an internal McLeod slave cylinder or an external?

Jim

 

[Dbteak]

Dbteak - do you have an internal McLeod slave cylinder or an external?

Jim

I have an internal throwout bearing mounted on a Tremec TKO. I am not sure which clutch I have but it may be stiff already. I will have to look but after thinking about it I may have gone from a 3/4 to a 5/8 MC. I will add my comments after I put the new M/C on from modern drive lines. Not sure when I will get to it though.

Doug

 

[86Horn_EB_77]

Thanks for the feedback. I went out and measured all the lever arm lengths on the old stock clutch linkage last night - and did some torque/force calculations assuming an 80 lb force input on the clutch pedal - probably high, but I don't think it matters.. Then I made up an excel spreadsheet and plugged in a 3 5/8 lever arm for the hydro master cylinder (about the best I'm able to do without our tearing up the firewall). Then I made some assumptions about the area of the internal hydro slave piston (2 inch dia piston with a 1 inch diameter hole in the middle for the input shaft).

The stock linkage gives you about 900lbs of force at the t/o bearing. The hydro (with 3/4 inch dia master) gives me just less than 1200lbs of force at the t/o bearing. Both of these assume an 80lb clutch input.

In reality, I need to work backwards: the pressure plate is going to require some unknown force to actuate it, and this will transfer back thru either actuation system. My numbers say that the hydro system has greater mechanical advantage and should have an easier pedal - but we'll see...

I can't seem to attach my xls file but if anybody needs it - send me a PM with your email.

Jim