Hydraulic Clutch Problems

Ferf · Jun 21, 2012

I am having problems with getting my hydraulic clutch to work properly in my '65 coupe. My setups is as follows:

- Tremec TKO transmission
- Centerforce DF161739 Dual Friction Clutch
- Quicktime Bellhousing
- Late model clutch fork
- Wilwood Master Cylinder with .750" Bore
- Slave Cylinder kit from Dazecars

The clutch has been bled numerous times and there is 1" of throw at the slave cylinder. We are having problems getting the clutch to fully disengage. At times it can be difficult to put into gear and reverse always grinds even when going 1st to reverse. If we adjust for additional preload then the clutch starts to slip in 3rd and 4th gear.

As stated before, the clutch has been bled many times. We have replaced all the lines and put in a different master cylinder. The trans has been pulled and everything looks okay with the clutch and everything else. We are stumped. Any ideas?

horse sence · Jun 21, 2012

i have the same problem with my 35 ford it has a t5 i need atleast another 1/4 inch throw , i have the 3/4 inch bore master cylender the clutch pushes very easy ,so i am going to try a 1 inch bore to see it it will travel just a little further

horseballz · Jun 21, 2012

May be a dumb question, but when you installed the slave cylinder, did the bleeder end up on the top or the bottom of the slave? If on the bottom, pointing down, you can bleed it a gazillion times and still not get all the air out. DAMHIKT!
My $.02,
Gene

Rusty67 · Jun 21, 2012

That centerforce is a dihpram type clutch. You need at least 1 1/8 inch of throw to disengage it. If you could get between 1 1/8 to 1 1/4 inch of throw that would be ideal. Are you sure you are geting full throw from your clutch master cylinder ? Maybe an adjustable pushrod on the MC will give you a little extra pedal travel and get you what you need.

horse sence · Jun 21, 2012

Rusty67 said:
That centerforce is a dihpram type clutch. You need at least 1 1/8 inch of throw to disengage it. If you could get between 1 1/8 to 1 1/4 inch of throw that would be ideal. Are you sure you are geting full throw from your clutch master cylinder ? Maybe an adjustable pushrod on the MC will give you a little extra pedal travel and get you what you need.

i am using the same master cylinder and slave cylinder as ferf however i am running a new old stock hipo clutch assembly,sounds like we are having the same problem
were not getting enough travel at the slave cylinder i have the clutch pedal adjusted
so high its hard to lift my foot up to the pedal i have more travel at the slave cylinder to go but the pedal hits the floor first, only thing i can think of is to increase the bore size on the master cylinder the extra fluid from the bigger cylinder may push the slave cylinder just enough to make it work my clutch can be pushed with ease so the bigger master cylinder should not be a broblem if it will move enough fluid to make a differance. how hard is it to push your clutch with your set up ferf ? oh bleeder is pointed up

horseballz · Jun 22, 2012

Folks,
This is likely to be a long post, so grab your favorite beverage and read on. This is the BEST setup I've seen for the master cylinder:

http://www.moderndriveline.com/catalog/hydraulic_masters.htm

Unfortunately, it was not available when I "home brewed" my hydraulic system. I did a BUNCH of research and found these problems and solutions:
>Different models of the Wilwood (and other brands) MC's, even with same bore size, have varying lengths of maximum stroke. A change from 3/4" to 1" master nearly "doubles" the amount of displacement, remembering that we are dealing with a circle for area=diameter divided by 2, squared x 3.14 and multiply that by the stroke for total displacement-volume. A small difference in diameter or stroke=a big change in volume.
Solutions:
1>Choose a master with the longest stroke available. The Wilwood "compact" and "integral reservoir compact" MC has a full 1.4" stroke as opposed to the 1.0" to 1.3" stroke of the "combination remote" and/or "compact remote combination" MC's.

2>Optimize the stroke that your pedal movement provides by:
A>Finding/measuring the point on your pedal that provides 1.4" of travel to the firewall in as close to a straight/perpendicular line as possible. Allow for carpet/padding, etc. or allow for a little extra stroke and put a small (1/4" to 3/4") wood or metal block as a stop under the pedal as the final step to avoid over traveling of the MC piston. On my 68, I don't recall if I had to drill the new hole in the pedal higher or lower the the stock one, but to get the MC in an optimum position required a slight relocation of the speedo cable. It was also quite close to the wiring harness. If you have a 68 (maybe 67, 69 & 70 are the same), I can provide you a template for the stiffener and spacer.
B>Remembering that as your pedal swings forward/backward, the point you have found on the pedal actually makes a slight arc, so position the MC straight to the center of that arc. This is not perfect, but at least minimizes the off-line up/down pressure on the piston.
C>Use a spherical rod end (heim joint) with a threaded coupler to attach/adjust the pedal to the MC rod. Besides putting a "stiffener" plate on the passenger compartment side of the firewall, you will likely need to put a spacer on the engine compartment side to allow proper fitment.
3>Most if not all of these difficulties can be avoided by using the Modern Driveline "mousetrap" system, linked above. The DazeCars "65-70 Mustang Offset Master Cylinder Pushrod" may do the trick, but I have not used it and suspect that it may not provide the proper stroke length.

As far as the slave is concerned, I do not like the DazeCars "T5 Hydraulic Clutch Bracket" (and many others similar to it), as it attaches to the transmission by those flimsy little tabs on the side of the transmission that simply don't seem sturdy enough for the task. The Modern Driveline bracket is a step in the right direction, except that, on a stock Ford T5 bell housing, the spot that attaches is kind of flimsy and insubstantial. The bracket design I like best is the one in the DazeCars "Tremec 3550, TKO 500/600 Hydraulic Clutch Kit" as it attaches to the bolts that hold the trans to the bell housing. Unfortunately, this style is not available for the T5 except from me for $50 plus shipping. I have a fabricator who will do these for us in water jet and leave them bare 3/8" steel plate.

I used a Wilwood 260-6089 for the 3/4" MC and the slave is for a late 80's - mid 90's chebbie full size pickup and has a bore of, I believe, .78-ish, is sturdy cast iron and has quite a long stroke available. FWIW, my setup has worked flawlessly for almost 3 years and 15,000 miles. I even still have the pedal assist spring installed, though I've been led to believe it is not needed or recommended.

Link to DazeCars:

http://dazed.home.bresnan.net/test#4

HTH,
Gene

hipo_p51 · Jun 23, 2012

To you folks with the "I gotta have the hyd clutch on my 65-6 mustang to be cool and fit in in the restomod crowd." Toss the hyd setup and go back to the Z bar people. I have a hyd setup and it is NO better than a properly adjusted Z bar.
My hyd setup went to together just fine from Mcloyds (i think thats the spelling). Anyways waste of time and money.
Just my .02 cents.
However I will continue to enjoy my car with that nasty thing in there, but the first hic-up that comes around. out it goes, and hello old friend, mr z bar!!

horseballz · Jun 23, 2012

hipo_p51,
I did not install a hydraulic clutch to "be cool and fit in" I did it because:

A>I'm an old fart with associated sore/weak legs, etc, but still enjoy the performance aspects of driving a stick.
B>My late model 5.0 block has no provision for a Z-bar pivot and by the time I'd have purchased the parts:
1-Bolt on Z-bar pivot
2-Clutch fork and clutch fork pivot to convert the T5 bell housing to driver side fulcrum
3-Various assorted hardware and refurb parts for original Z-bar
I would be well over the $160 it cost me to do the hydraulic setup!
C>Cable clutch setups suck IMHO

AND

C>We cannot use a Z-bar with most modern style integral power steering boxes and considering the suck factor of OEM "ram style" power steering, integral is the best way to go IMO.

If you like the Z-bar system, have at it, but it didn't make sense for my situation.
My $.02,
Gene

horse sence · Jun 23, 2012

right on Gene, uh thats a term we old farts used at one time,i like my manual transmition,but after years of packing drywall up and down stairs and elevator shafts
my knees are not in the best of condition any more either .the hydrolic clutch in my 35 is much easier to push than a z bar clutch all i need is just that little bit more throw so it will shift with out grinding gears, i have had problems with z bars as well
such as one of the bars bending or even snapping off ,not real fun at a stop light. Jim

Ferf · Jun 25, 2012

I had to go with a cable clutch or hydraulic clutch due to my headers. Since I heard many reports of headers causing the cable to snap in a cable clutch setup I went with the hydraulic clutch.

Back to the point at hand...

It seems that we go the preload adjusted properly as we could shift through the gears and there was minimal grinding in reverse. My uncle drove the car a few miles down the road with no problems...going through all the gears, down shifting, etc. He then procceded to turn around to head back and the pedal got soft on him. He had to pump it a few times to get it into gear. On the way back to the garage the pedal stuck to the floor. He was able to lift it up and pump the pedal a few times to get the car into gear. By the time he pulled back into the driveway of the garage, he was pumping the pedal about 15 times to get it into gear.

He said that there doesn't be any signs of a leak as he can't find fluid dripping anywhere. This is very similar to the problem we were having before replacing the master cylinder (we had thought that the MC was defective). Prior to replacing the master cylinder, all of the fittings and tubing was replaced just to be safe. My uncle also used teflon tape on all the fittings. With this being the second master cylinder and second set of lines and fittings, we are stumped on what the problem is.

Any ideas?

horse sence · Jun 25, 2012

it sounds like it is drawing air back into the system,is the bleeder screw seating
correctly in the slave cylinder and tightening all the way down ? or possibly drawing air back in at the hose ,thread tape may be allowing air to bleed back in to your system

Rusty67 · Jun 25, 2012

Firs things first, back to basics.

Number 1, did you bench bleed the master ?

Number 2, why are you using teflon tape at all ? Every connection to and from hard line should use flair nuts with flaired hard line. Make sure you use a flair nut wrench to tighten these so you don't round the edges off.

Number 3, can you post some pics of how your hardline and softlines are run.

horse sence · Jun 26, 2012

horseballz said:
Folks,
This is likely to be a long post, so grab your favorite beverage and read on. This is the BEST setup I've seen for the master cylinder:

http://www.moderndriveline.com/catalog/hydraulic_masters.htm

Unfortunately, it was not available when I "home brewed" my hydraulic system. I did a BUNCH of research and found these problems and solutions:
>Different models of the Wilwood (and other brands) MC's, even with same bore size, have varying lengths of maximum stroke. A change from 3/4" to 1" master nearly "doubles" the amount of displacement, remembering that we are dealing with a circle for area=diameter divided by 2, squared x 3.14 and multiply that by the stroke for total displacement-volume. A small difference in diameter or stroke=a big change in volume.
Solutions:
1>Choose a master with the longest stroke available. The Wilwood "compact" and "integral reservoir compact" MC has a full 1.4" stroke as opposed to the 1.0" to 1.3" stroke of the "combination remote" and/or "compact remote combination" MC's.

2>Optimize the stroke that your pedal movement provides by:
A>Finding/measuring the point on your pedal that provides 1.4" of travel to the firewall in as close to a straight/perpendicular line as possible. Allow for carpet/padding, etc. or allow for a little extra stroke and put a small (1/4" to 3/4") wood or metal block as a stop under the pedal as the final step to avoid over traveling of the MC piston. On my 68, I don't recall if I had to drill the new hole in the pedal higher or lower the the stock one, but to get the MC in an optimum position required a slight relocation of the speedo cable. It was also quite close to the wiring harness. If you have a 68 (maybe 67, 69 & 70 are the same), I can provide you a template for the stiffener and spacer.
B>Remembering that as your pedal swings forward/backward, the point you have found on the pedal actually makes a slight arc, so position the MC straight to the center of that arc. This is not perfect, but at least minimizes the off-line up/down pressure on the piston.
C>Use a spherical rod end (heim joint) with a threaded coupler to attach/adjust the pedal to the MC rod. Besides putting a "stiffener" plate on the passenger compartment side of the firewall, you will likely need to put a spacer on the engine compartment side to allow proper fitment.
3>Most if not all of these difficulties can be avoided by using the Modern Driveline "mousetrap" system, linked above. The DazeCars "65-70 Mustang Offset Master Cylinder Pushrod" may do the trick, but I have not used it and suspect that it may not provide the proper stroke length.

As far as the slave is concerned, I do not like the DazeCars "T5 Hydraulic Clutch Bracket" (and many others similar to it), as it attaches to the transmission by those flimsy little tabs on the side of the transmission that simply don't seem sturdy enough for the task. The Modern Driveline bracket is a step in the right direction, except that, on a stock Ford T5 bell housing, the spot that attaches is kind of flimsy and insubstantial. The bracket design I like best is the one in the DazeCars "Tremec 3550, TKO 500/600 Hydraulic Clutch Kit" as it attaches to the bolts that hold the trans to the bell housing. Unfortunately, this style is not available for the T5 except from me for $50 plus shipping. I have a fabricator who will do these for us in water jet and leave them bare 3/8" steel plate.

I used a Wilwood 260-6089 for the 3/4" MC and the slave is for a late 80's - mid 90's chebbie full size pickup and has a bore of, I believe, .78-ish, is sturdy cast iron and has quite a long stroke available. FWIW, my setup has worked flawlessly for almost 3 years and 15,000 miles. I even still have the pedal assist spring installed, though I've been led to believe it is not needed or recommended.

Link to DazeCars:

http://dazed.home.bresnan.net/test#4

HTH,
Gene

cool Gene ,i didnt know you spoke greek after working all day its all greek to me lol

Hydraulic Clutch Problems

Ferf

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horse sence

horseballz

Rusty67

horse sence

horseballz

hipo_p51

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horseballz

horse sence

Ferf

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horse sence

Rusty67

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