I'm in the process of refurbishing a '90 F350 diesel and one of the things I'm doing to it is swapping the E4OD automatic for the ZF 5speed. I'd like to set up a mechanical clutch linkage from the pedal to throwout fork and I was wondering if anyone here has fabricated something like this before. I was thinking of copying the linkage on my 62 F250 but would need to massage the dimensions for the newer truck.

 

ypu may be able to get something like this from a junkyard?????

 

i would stick to hydraulic.

 

If you can present some good reasons why, I'm all ears. I've not had good luck with hydraulic clutches in the past and I especially don't like the F-series plastic setup. I also like to be able to adjust my pedal to release just above the floor, which as far as I know you can't do with a hydraulic setup.

 

No ZF ever came with a mechanical clutch, as you probably know. I know that converting from a mechanical to a hydraulic clutch on an early 80's pickup requires a new bellhousing, so I would imagine there's not an easy way to convert using the same bell. I haven't compared the two bells side by side to see what the difference is, but I bet you're in for quite a bit of fabrication work, if it's even possible.

It would be far, far easier just to deal with a hydraulic clutch. There are millions of trouble-free hydraulic clutch setups installed in F-series pickups, so I don't know what you might have had a consistent problem with.

 

all that andy said.

with proper setup and maintenance you should not have a problem with the hyd. clutch and the zf trans.

 

I had an 89 F150 with the M5OD that didn't give me any trouble per se, I just didn't like the feel of it (no adjustment, sometimes sluggish rebound). The 88 F250 I had was more of a problem: first the little crown shaped bushing under the dashboard broke, then the master cylinder rod wouldn't line up so that the new bushing would stay for long, then it wouldn't hold the bushing at all, and finally I drilled it for a cotter pin and put washers on but eventually the metal wore through and it needed a new master cylinder. I've also had the clutch master cylinder (not in a Ford truck, this was a VW car) fail such that the pedal would sink and eventually stop giving enough travel to disengage fully.

I know that Ford made millions of these and that most people didn't have a problem, but remember, I'm working on a truck that's almost 20 years old and is a swap job at that. The chances of having a problem with anything that was marginal in the original design are higher is all I'm saying.

I may well go with the hydraulic setup from my ZF donor truck, we'll see. The earlier comment about hitting up a junk yard, if only for ideas, is where I may start. I've already got an idea I may at least attempt - I was going to lay out a linkage like a really old passenger vehicle (think 1930s) or many heavy trucks had, where the clutch pedal is supported by a curved rod that goes down and rotates on an axle that runs perpendicular to the frame and comes out just inside the frame rail, either in front of or behind the release fork. An arm would attach to the end of the axle and connect to the throwout fork with an adjustable linkage. I'd also need a spring somewhere to help the return motion. The hard parts would be finding good spots on the bottom of the cab to mount the bearings for the axle assembly and getting the geometry of the driven end (the shorter arm pushing the throwout fork) correct so as not to push the fork up or down, just straight back.

OK, so I might have given this design more thought than I let on, but I wanted to see if anyone else had tried this before. Thanks for the feedback (even if you're saying I'm nuts), it's all helpful.

 

A 1930s set up, huh?

You said it: """even if you're saying I'm nuts"""

However, I've seen a lot of posts about the juice clutch issues here. Seems like most get fixed.

My dad's '58 F600 had a juice clutch, so it's not like it's a new idea....

The stock parts for your truck are certainly in the yard somewhere, and replacements should be available from NAPA or other fine aftermarket supplier.

Re-read your paragraph about through-the-floor pedals and bars and and....

How you gonna keep that working when the engine torques over a bit or you get on an uneven surface with a bit of the old frame/cab flex going?

Your truck--take the long road if you must, but I say juice clutch and forget the legos meets tinkertoys via erector set homebuilt set up for mechanical linkage.

 

Good points, 85e150six4mtod. Like I said, I may very well abandon this plan once I get to this phase (I'm still cleaning and POR-15ing the fame, tranny swap is next). A properly executed hydraulic clutch is OK, but the all plastic assembly our trucks use makes my skin crawl. Case in point, when I posted my last update to this thread and went back to the forum the top thread was about...a hydraulic clutch linkage problem!

I played with legos and an erector set a lot as a kid, how'd you guess?! This setup will be welded mild steel though

As for my design, the setup my '62 has may be a better template. I've found some diagrams of the setup from the late 60s, which is very similar:


If the plane of the 90's stock pedal is close enough to the inside of the frame rail, I might be able to get away with welding something to the top of the pedal and use a rod running straight down, behind the pedal like the older linkage uses. Then I just need to fab a mount for the intermediate pivot, the pivot itself, and the rest of the way into where the slave cylinder goes should be a short, straight rod.

Issues with the driveline torquing aren't apparent on my '62, and that has a honking grapple skidder engine in it with a medium duty truck tranny (and only one non-stock clutch linkage part) so I'm not too worried about the F350. If I do pull this off I'll document it and post it here.

Cheers!

 

My 1988 F-150 has a hyd. clutch, with a CONCENTRIC SLAVE CYLINDER--this is bad, as it requires the tranny to be pulled, to replace the slave cyl., should it fail. (It actually surrounds the trans input shaft! Clearly, not one of Ford's "better ideas.") Where I live, that's an almost $800. job, if you do the $200. clutch and press. plate, while you're in there (as you should).

My 1997 F-250 is also a hyd. clutch, but because it is a 460 with the ZF 5 spd, it has an EXTERNAL SLAVE CYLINDER. If it fails, it's very easy to replace.

My 1981 F-100 has a purely mechanical linkage.

I don't know what the bellhousing issues might be, but I would AVOID THE CONCENTRIC SLAVE CYL. if at all possible. I would guess that you might just have to fab up an adapter plate for an external slave cyl., in order to make it fit on a non-460/diesel bell housing, but I'm just guessing. That slave cyl. alone is, I believe, around $100. (but that may have included the master as well--can't remember).

Let us know what you decide?

 

The ZF transmissions behind diesels all had external slaves.

 

^^^^^ +1. External slave is a much more "intuitive" design, basically a hydraulic counterpart to the mechanical.

Anecdotal experience with clutch externals:

• Friend's '70s VW 412 - didn't understand why (1) brake fluid leaked on the floorboard (2) Hard to start in gear and (3) no one stocked a clutch cable for it. DUH, hydraulic clutch, M/C was shot.
• My '80 Omni, VW engine/tranny, clutch cable broke in downtown Ann Arbor. Powershifted it into a PARALLEL parking spot ON THE STREET. Had to bicycle back to the spot where the cable broke to find the clip that holds the ball-end (falls to ground when cable breaks). Biked out to Naylor Dodge, installed the cable on the street.
• Wife's '83 F150 300 4-speed SROD. Mechanical linkage. Pivot mounted on the tranny broke off. For those familiar, most of them had their own little bracket, which bolted on via two of the bellhousing bolts. Not this one; it screwed DIRECTLY into the tranny case. Broke off flush! We fabbed in one of the bracket-style pivots from Broncograveyard; fortunately it lined up.
• My '89 Colt, hydraulic clutch, purchased at 43,000, traded in at 119,000, not a whisper of trouble
• Current '96 Saturn wagon, purchased at 30,500, presently at 107,500, not a whisper of trouble. I'm on a Saturn site, and they do fail, but it's about $150 to replace the whole system (it's a sealed unit on the Saturn). When they fail, they usually get weak, rather than just failing outright
• Wife's '95 F250 PSD ZF (external!), presently 148,500-ish, no problems reported by previous owner, none by us (< 1000 miles)

Summary - all three (cable, linkage, hydraulic) can fail. The hydraulics typically aren't adjustable (I'll have to look at the slave on the wife's schooner). The cables/linkages tend to fail all at once, whereas when the hydraulics go, they get weak over time (gradual failure of master or slave piston seal, I reckon). If you do fab a mechanical, I'd recommend making it "undo-able"; keep the firewall, pedal, fork, etc. such that you can revert to the original just in case.

 

I've been done with and driving my ZF swap for about two weeks now, and I ended up going with the factory hydraulic setup. I don't like it! But it works (for now) and was easy to set up. Oh, that "crown" bushing that goes in the pivot for the master cylinder? Yeah, went through three of them before I had it set up so it wouldn't destroy the bushing in about 10 pedal strokes. I had to grease the joint (I think it's dry from the factory) and also drill the assembly to install a cotterpin to keep the master cylinder arm from falling off. My only other observation is that the pedal is harder to push in than the pedal on the Mack model U dump truck I used to drive.

 

sounds like something is still not right.

glad you got it together.

 

It's not supposed to be that hard to push the pedal? Hmm. I didn't see anything adjustable on the hydraulic setup, is there something I should look at?

Thanks quicklook, it was an ordeal to get the truck totally done in a month but it was worth it!