Jump to content

Recommended Posts

Well, progress has been slow due to work and family, but I spent a solid 6 hours on the CJ-7 project last night.  I bought a new clutch linkage kit, as my lower and upper clutch rods were worn half way through, and the bellcrank was a mess.  The new kit has an adjustable lower linkage rod with a ball joint instead of the old bent solid rod. 

 

And.....cue swearing.  The 4.0 swap exhaust routing must be slightly different from stock (it's some kind of welded header instead of a cast iron manifold) because the ball and socket joint whacks the exhaust down tube solidly when the clutch pedal comes back to rest. 

 

After adjusting things for about an hour and trying the lower rod backwards, I conceded that it wasn't going to work and ordered a set of heim joint linkage rods to go with my nice new bellcrank and bushings.  I have to say, the stock setup is a pretty questionable system. I guess maybe it gets points for simplicity, but for stoutness it is lacking.

 

  I know lots of folks have difficulty with the release lever jumping off the clutch fork, I wonder if there is a way to modify that to accept a ball and socket end for a positive mount instead of the old spring tension junk...

Share this post


Link to post
Share on other sites

This late CJ mechanical clutch linkage is "questionable" as you share, actually it's notorious.  In the late '80s, I was on assignment for OFF-ROAD Magazine at Arizona, shooting still photos of a valued advertiser's heavily modified Jeep CJ.  He had your linkage on his V-8 upgrade powered Jeep.  At the owner's insistence, I perched to catch photos of the Jeep "leaping" over a high berm, a maneuver that made magazine covers in the day—and even now.  Not sure what the "message" is here.

 

As the Jeep landed, the clutch link jumped off the release arm and left the CJ with no way to operate the clutch.  Fortunately, the photo was much to the owner's liking, as it was the last pic in the set! 

 

Advance Adapters has been solving clutch linkage problems on Willys and Jeep vehicles from the MB WWII model forward.  I've used several of their solutions to much satisfaction.  They also have clutch links with a half-ball and a universal threaded stem that could possibly help with your current linkage.  The stem would pass through a hole you drill in the release arm end, and the stub would prevent the linkage from jumping out of the arm end.  You'd still use a return spring.  I'm not thrilled with this approach, as you're drilling a relief hole in a stamped, not all that heavy duty release arm.

 

For those interested in this issue, I'm sharing the schematic and OEM parts layout.  I have included an example of the factory hydraulic clutch linkage used on the 2.5L Iron Duke GM fours (used to 1983), diesels (export only) and the RHD 4.2L export models.  This RHD 4.2L model's hydraulic linkage setup uses the same release fork as 60Bubba's CJ-7 LHD 4.2L model—compare the part numbers.

 

AMC 2.5L engines, introduced in 1983 and not included in the illustrations, use hydraulic clutch linkage but have a cross-housing release arm that does not operate in the same direction as the CJ 4.2L LHD factory release fork.  The cross-housing arm is similar to the clutch linkage arrangement on the XJ Cherokee 2.5L fours introduced in 1984.  The last illustrations are the busy mechanical linkage like on 60Bubba's CJ-7.  On any of these PDFs, you can zoom-in on the illustrations or part numbers for clarification:

 

pdf.gif  1981-Up Jeep CJ-7 Clutch Linkage.pdf

 

The best solutions involve hydraulic linkage and eliminate the plethora of mechanical linkage parts...Before plunging further, check out the Advance Adapters catalog online (click here to http://www.advanceadapters.com).  Consider a call to 1-800-350-2223 and connect to the helpful, Jeep-friendly tech line.  Advance Adapters is located at Paso Robles, not too far from your current home, 60Bubba.

 

Moses

Share this post


Link to post
Share on other sites

What I'm seeing on the AA website for Jeep clutches is a chain and bellcrank setup.  I think that would solve the issue with binding due to engine movement or frame flex, but it still seems pretty complicated.  I'm going to proceed with the new brackets and bellcranks I already installed, and use the rod end joints that are in the mail.  I think this will solve all the issues I'm likely to have.  Given the investment in mechanical and cosmetic upgrades, She Who Must Be Obeyed has decreed there will be no hardcore offroading in this Jeep's future. 

 

Sounds like an invitation to build a trail rig to me...

Share this post


Link to post
Share on other sites

Good idea, all around...The chain system is great for vintage models with through-the-floor pedals, light years ahead of the OE cable linkage.  Hydraulic linkage can be fitted fairly easily with fabrication of a hydraulic slave cylinder mount, but you're right, the cost of a hydraulic master cylinder, a slave and hose or tubing adds up.  You'd also need to find pedal linkage from a four-cylinder model with a master cylinder. 

 

By sheer coincidence, each of the '80s CJs that I used for projects had four-cylinder engines originally—and stock hydraulic clutch linkage.  I modified these hydraulic systems to work with OE six-cylinder clutch and bellhousing layouts.  An Advance Adapters bellhousing (stock 4.2L replacement) has a provision for the slave mount.  I was fortunate in that the clutch pedal setup, master cylinder and slave were usable.  One project had the Iron Duke four-banger, the other an AMC four.  Actually, these were both good engines, just not "magazine material".

 

You'll be fine with your planned heim joint arrangement.  Many Jeep CJs with your clutch linkage have made it over the Rubicon Trail, though for the sake of your happy home, I'm not suggesting that you "test" your pristine restoration job on such trails...Tennessee and S.E. clay mud will be plenty.  Once you're satisfied that the clutch return spring at the release lever will keep all of this aligned and in place, it should work well.  You do need the return spring to assure that the clutch release (throwout) bearing is not riding on the clutch cover fingers when the clutch pedal is released. 

 

A general tip for AMC era CJs:  Make sure the clutch pedal height from the floor is adjusted properly.  That height assures adequate linkage travel.

 

Moses

Share this post


Link to post
Share on other sites

Here is the finished linkage setup, before torquing everything down.  It feels very secure, and the slop is completely gone.  Once I get the new wiring harness ready for an engine start, I'll be able to check the overall adjustment and make sure I haven't adjusted the linkage to the point that it is "riding the clutch."  I think for a road vehicle with only mild trail use, this is about the optimal setup.

 

 

post-399-0-58613300-1418781319_thumb.jpg

post-399-0-96660800-1418781332_thumb.jpg

post-399-0-71645100-1418781344_thumb.jpg

post-399-0-62021800-1418781356_thumb.jpg

post-399-0-22138600-1418781369_thumb.jpg

Share this post


Link to post
Share on other sites

×
×
  • Create New...