Technical Need Hydraulic Clutch Help ASAP

Maybe a good chance you need a different pedal assembly....do you know how the brakes work

 

The simplest thing to try is to lengthen the clutch arm. Easy to build a temporary arm to try it by putting a piece along side the original with several holes and shim the slave out to center on it mounted on one bolt.

I don't know if those dual function master cylinders come in different piston sizes. A larger diameter slave is another option. Changing the pedal ratio would be difficult.

 

Dave - before you physically modify that pedal box in an effort to increase the mechanical advantage of the system, I would look at what else may be available for master cylinder and slave cylinder bores. You can effectively increase your mechanical advantage that way, and not disturb your brake pedal ratio.

 

Also - a '32 clutch release arm is nearly 4", which can help as well.

Are you running a Borg and Beck pressure plate by chance?

 

Great suggestions guys.

The trans is completely rebuilt and I checked and lubed the collar, the shaft and all points of contact before assembly.
As @OldBuzzard mentioned While the 3.5 lever is shorter than the 6.5 lever GM used in the trucks, I have used this combo successfully before. Although I don't honestly remember how long the lever was on the truck I used it on. I believe Ford has 3 different lengths of levers???

I did just look at the hanging pedals Speedway sells they definitely have a better ratio than mine. Does anyone know if the fit the GM truck master?

 

What pressure plate are you using? That throw out arm in the can is designed for around a less than robust spring pressure. Most pressure plate levers operate at a 3-1 ratio. If you have a 3000 lb. pressure plate, it will take 1000 lbs on the throw out bearing to release it. The problem more than likely isn't the pedal assembly as it is what your asking the bell crank to do. I used that fork on a dragster clutch with 600 lbs of pressure plate force. It worked fine. But with a heavy plate, it was impossible to to depress a clutch pedal.

 

Hi Cory, thanks for responding.
I am using a Borg & Beck pressure Plate.
I'm kind of tied into the gm truck master because of the firewall mount. I'm not aware of any other bore sizes available in that configuration of master. The slave is an easy modification that just requires fabing a new mount. What size bore on the slave would give the hydraulic advantage I need?

 

@wfo guy The Ford trans is mated to an early Caddy engine. The pressure plate and clutch where included with the car when I bought it, so I have no info on them other than they are new/unused. The car wasn't finished or runningbwhen I bought it.

 

There should be a 1 1/8" bore slave available - I know a 1 1/16" is for sure. That's a common slave cylinder used on GM pickups from the '60s on up until '87.

I would also seriously consider getting rid of that B&B pressure plate. There's probably a diaphragm pressure plate available that will lessen the effort required to disengage. I went through that exercise this time last year on the 5w.....

 

Adding to the 3.5" arm does not seem to be an option due to space problems. If it was mine I think I would try to find a slave cylinder that would develop pressure enough to operate your clutch arm as it is. Let the hydraulics do the work.

 

@CTaulbert
The pressure plate in the car now appears to be a 10" early Ford style. I have a new 10" diaphragm pressure plate here. I'm not sure what it came out of but the distance from the pressure plate surface to the mounting flange is the same as an early Ford 9' pressure plate I have laying around. The height of the diaphragm springs and the fingers on the early for P. Plate are the same also. It appears the mounting holes would line up too.
Tempted to pull the engine and trans and give it a go...

 

That pressure plate sounds like '49^ Merc, I think those were B&B, Ford Long style PP use a different bolt pattern. B&B uses 6 equally spaced bolts as do some diaphragms, but I'm pretty sure there are also diaphragms with Long style bolt pattern. Regardless, the lower pressure plate might work but still, with the present master/slave combo there is not a lot of pressure available with the 4-1 pedal ratio. Stepping up to 6-1 gives you 232# at the lever.
With the diaphragm PP consider the different Belleville springs, flat and bent. Flat springs use a t/o bearing with a rounded, or tapered face and the bent finger will use a t/o with the typical flat face like you already have. Flat fingers will sometimes stick to the floor under high RPM, but I doubt that will be an issue for you.

 

Well got pissed and tanked the engine. Put a 13" long box end wrench over the clutch lever and it was all I could do to disengage the clutch. Not to surprised by this.
Pulled the pressure plate in hopes of trying my 10" diaphragm p plate. No luck the one on the engine is an 11". This thing looks pretty beefy with 9 sets of springs. Most of the early Ford stuff I've seen have only 6 springs. That could be part of the problem too???

 

Any good, long time, local clutch rebuilders in your area? Maybe they could just change out the springs for less strong ones. If you do wind up keeping the 11" PP check for adequate clearance by the trans adapter and the counterweights on the levers.
There is a number for a diaphragm that I saved when I saw it posted on Ford Barn, it's a NAPA CA30, but unfortunately that is a 10" and BTW, your present PP is Long style. When you mentioned it being a Borg & Beck I commented on it being from a '49-'53 Merc, but it's an 11" Ford truck Long style PP.

 

Aaaahhhh, thanks for the education @Fordors. So it is an 11" Ford truck unit. What years was it used?

No good rebuilders in my area. If can get a diaphragm style to replace it, will it be worth swapping over? This p plate is way beefier that the one in my previous truck. That may be why the same basic components aren't getting the job done. That and a bad pedal ratio.

I'm just getting frustrated as this car needs to be in Indiana for interior by this weekend.

 

Most over on the 'barn rave about Fort Wayne Clutch in Indiana, and in my area it's Surge Friction in South Holland, IL but that doesn't help you with the time frame you are working in. Sorry, I don't know what years that PP was used in but for sure someone will over on Ford Barn.
Sorry, I should have commented on the 11" diaphragm. A good counter person at NAPA that knows their business should be able to help, keep in mind you need the Long style bolt pattern so you don't have to redrill the flywheel.

 

I echo Fort Wayne Dave - if you order from them tomorrow, you'll have it on Wednesday since we're close to them. I know they have 11" pressure plates too.

 

Just to make sure - that's the only pressure plate pattern that the flywheel is drilled for?

 

Thanks @Fordors

Hey @CTaulbert do you think a diaphragm type plate will soften up the pedal enough to make it worth while? Also any idea of the application/year of the plate I need? I can call them tomorrow am, but need to now what to order.

 

Yes that is the only pattern @CTaulbert

 

If you're going through the trouble of a pressure plate change, I would trying to find a diaphragm that works. The difficulty is going to be finding one in that "3 pairs of 2" mounting pattern.

I've been running an off the shelf GM pressure plate behind my sbc in the 5w, actuated by the large diameter Ford throw out bearing. It did require a little grinding on the diaphragm finger inner diameter to clear the input shaft when the fingers were depressed. It was nothing 5 minutes with a barrel sander couldn't solve.

 

Thanks Cory.

 

Maybe a restriction in the hydraulic system. Start cracking the bleeders and line connections and see if you get the pedal to move?

 

I bought a RJays just like that a couple years ago. The pedal ratio seemed way to short, called RJay's and got the same answer you did, sold a ton of them, no complaints. Since I had room from foot pedal to floor I opted to lengthen the pedal between the push rod hole & clutch foot pad. Ended up with a 6:1 ratio. All you have to do is the math of his pedals it doesn't lie...........................................

 

I run the same master/slave combo as you're running. I build my own pedal assembly with a 5.5:1 ratio. If you have room, make your pedals longer.


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If you have used this master/slave combo before, and the only thing that is new is the pedal assembly. I feel that is your problem. If you can, compare the pedal assembly to the one that has worked for you in the past.

Feel free to give me a call if I can help. 281-376-5932 -Danny


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The picture of the Rjays pedals sure look to have a higher pedal ratio as compared to the Ansen style pedal assemblies we have used in the past.

One thing I don't think has been mentioned yet; if the pedal ratio is as far off as it appears to be, you will also find higher than normal pedal pressure will be required for braking.

Ansen pedals have 5-1/2 to 1 ratio; what do your pedals measure out to be?

 

If that pedal ratio is indeed 4 to 1 as calculated by a previous post, the brakes will not work correctly either without a booster which you do not have. To stop the car as it is now, you will have to weigh 400 lbs and stand on the pedal with 3 feet.

 

I had set up the hydraulic clutch in my '59 Ford, I made up a plate to mount the new dual master and clutch master to the firewall. It was convenient to mount the pivot lower on the pedal with what I made up. The pressure at the pedal was ungodly. Clutch master is a 3/4" Wilwood, slave is a 7/8" Speedway item.

I moved the pivot up to the stock location, also made a new mounting plate and mounted the clutch master up higher accordingly. It works quite nicely, pedal effort is comfortable. I had fooled around making a bellcrank and extending the OG plate downward, all I did was machine up a bunch of steel for nothing. I think a higher ratio will fix it.

 

Just wanted to follow up and thank everyone for the help.

I seemed to have solved the problem with a combination of the suggestions above.
I moved up to a 1 1/16 bore slave and installed a lighter duty pressure plate.

The clutch is still stiff but will be drivable.

I will be lengthening the pedals 2 inches (for a 5+ pedal ratio) soon. This should get me where I need to be.

The car is going off to interior tomorrow and and won't be running for a while yet, but I'm confident it's good to go.

Thanks again to all who helped.