clutch hypothetical question
Thread Starter
CF Veteran
Joined: Nov 2011
Posts: 7,387
Likes: 10
From: City of Trees, CA
Year: 93 2 door
Model: Cherokee
Engine: 4.0
ok I have a hypothetical about an xj clutch. good luck making any sense of this. but any feedback is greatly appreciated
I had this idea about how to make crawling easier and I've never seen this mod before (probably because it destroys the clutch)
I know there are performance clutches that do this. I dont want to buy or install one
the question is, will making this mod destroy my clutch? I dont know all the mechanics of a clutch
here is your crudely drawn side view of a clutch in a cherokee.
the triangle is the pedal. the red is the "sweet spot"

I want to weld a "stopper" of sorts. if that makes sense. right at the end of the "sweet spot"

so when I apply pressure to the clutch to shift gears, it will stop right at the end of the sweet spot.
that way theres less room for error in a quick shift situation
in theory, I would be able to shift much quicker right? less chance of stalling..

see where the clutch pedal would be stopped by the welded piece?
the only thing that worries me is that the pedal will never be pressed all the way down. I dont know if that's detrimental
I had this idea about how to make crawling easier and I've never seen this mod before (probably because it destroys the clutch)
I know there are performance clutches that do this. I dont want to buy or install one
the question is, will making this mod destroy my clutch? I dont know all the mechanics of a clutch
here is your crudely drawn side view of a clutch in a cherokee.
the triangle is the pedal. the red is the "sweet spot"

I want to weld a "stopper" of sorts. if that makes sense. right at the end of the "sweet spot"

so when I apply pressure to the clutch to shift gears, it will stop right at the end of the sweet spot.
that way theres less room for error in a quick shift situation
in theory, I would be able to shift much quicker right? less chance of stalling..

see where the clutch pedal would be stopped by the welded piece?
the only thing that worries me is that the pedal will never be pressed all the way down. I dont know if that's detrimental
You need to press the clutch all the way down to trip that switch so you can start it. Either remove the switch (which is a dumb idea) or rig it somehow.
It's going to be a pain in the ***. Not to mention, it probably won't work right and it doesn't seem like it would be worthwhile.
You probably won't be able to shift any quicker anyway.
It's going to be a pain in the ***. Not to mention, it probably won't work right and it doesn't seem like it would be worthwhile.
You probably won't be able to shift any quicker anyway.
Thread Starter
CF Veteran
Joined: Nov 2011
Posts: 7,387
Likes: 10
From: City of Trees, CA
Year: 93 2 door
Model: Cherokee
Engine: 4.0
I'm thinking about doing a removable one eventually and testing it out. and I've owned two xj's that didnt require being in 1st gear or putting the clutch down in order to start it so that didnt even cross my mind haha.
it was just a thought
it was just a thought
CF Veteran
Joined: Aug 2011
Posts: 1,031
Likes: 4
From: Blue Springs, MO
Year: 1993
Model: Grand Cherokee
Engine: 4.0L Laredo
You're crazy! OK, now that we've established that you are indeed quite insane.. When you depress the clutch pedal, force is applied to the 'release bearing' or throw-out bearing as it is often called, by way of a lever that is bolted to and pivots on your bell housing. The bearing sits on the trannys output shaft adjacent to 'fingers' on the pressure plate which is bolted to the engine(flywheel). w/o going into too much tekkieness, the force on the pressure plate fingers allows the clutch to slip. The 'sweet spot' you refered to (nice drawing by the way) is where the clutch slips enough to effectively disengage the tranny from the engines applied power. That said, I don't see any real problem with doing what you described, but i'd make dam sure to go past the 'sweet spot' at least an inch or so, because you want to be certain you can fully disengage the clutch (like for actually stopping) Now.. Since I too am certifiably wacko, I'd suggest you look down under the dash where the clutch pedal mounts, and see if you could wedge a hard piece of rubber, or a small block of wood to make the pedal 'bottom out' just below your 'sweet spot'. Just duct tape it in place, or wire it, then if it doesn't work as you'd hoped, you won't have an unsightly steel bar welded to your floorboard. (I can hardly wait for the flamers!) I have to go now, it's lights out here at the sanitarium. Good Luck!
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Thread Starter
CF Veteran
Joined: Nov 2011
Posts: 7,387
Likes: 10
From: City of Trees, CA
Year: 93 2 door
Model: Cherokee
Engine: 4.0
You're crazy! OK, now that we've established that you are indeed quite insane.. When you depress the clutch pedal, force is applied to the 'release bearing' or throw-out bearing as it is often called, by way of a lever that is bolted to and pivots on your bell housing. The bearing sits on the trannys output shaft adjacent to 'fingers' on the pressure plate which is bolted to the engine(flywheel). w/o going into too much tekkieness, the force on the pressure plate fingers allows the clutch to slip. The 'sweet spot' you refered to (nice drawing by the way) is where the clutch slips enough to effectively disengage the tranny from the engines applied power. That said, I don't see any real problem with doing what you described, but i'd make dam sure to go past the 'sweet spot' at least an inch or so, because you want to be certain you can fully disengage the clutch (like for actually stopping) Now.. Since I too am certifiably wacko, I'd suggest you look down under the dash where the clutch pedal mounts, and see if you could wedge a hard piece of rubber, or a small block of wood to make the pedal 'bottom out' just below your 'sweet spot'. Just duct tape it in place, or wire it, then if it doesn't work as you'd hoped, you won't have an unsightly steel bar welded to your floorboard. (I can hardly wait for the flamers!) I have to go now, it's lights out here at the sanitarium. Good Luck! 

Senior Member
Joined: Jul 2010
Posts: 620
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From: Clover, S.C.
Year: 1998
Model: Cherokee
Engine: 4.0L
Just wondering if the reason for this is so you can have the clutch "just barely disengaged" and still have your weight on the pedal, in other words to brace yourself over bouncy terrain for a few seconds & then re-engage the clutch just a little quicker?
I kinda see where you're going with this, but is the reason being that your clutch is engaging really high up on the pedal stroke?
Also is your clutch hydraulic? If so, have you tried bleeding it?
I kinda see where you're going with this, but is the reason being that your clutch is engaging really high up on the pedal stroke?
Also is your clutch hydraulic? If so, have you tried bleeding it?
CF Veteran
Joined: Aug 2011
Posts: 1,031
Likes: 4
From: Blue Springs, MO
Year: 1993
Model: Grand Cherokee
Engine: 4.0L Laredo
"I know there are performance clutches that do this. I dont want to buy or install one the question is, will making this mod destroy my clutch? I dont know all the mechanics of a clutch
^^That was the only reason I tried to go into a little detail.^^
Member
Joined: Apr 2011
Posts: 121
Likes: 0
From: Hendersonville, TN.
Year: 1990
Model: Cherokee
Engine: 4.0 I6
A clutch bump stop .. Sounds like a good idea but I'm not convinced you will really shift faster just save a millisecond not pushing the clutch in all the way
I think the only way to make the clutch disengage faster would be to make the rod coming out of the master cylinder longer and the pedal shorter

Box = master cylinder
Black oval = plunger
Stick thing = plunger rod connected to pedal
Dotted line = location for plunger to be for "sweet spot"
( picture not even close to scale)
It's pretty simple longer pedal more leverage but more movement to get it all the way down
Shorter pedal quicker ..
The shaft shouldn't make much Much difference because you still have to push the plunger in the same distance but with the longer one would make your pedal closer to you
But the shorter one would let you make the bumps stop part shorter and keep the pedals all in one line more or less
( someone pease correct me If I'm wrong)
But I believe that the best way is to have a shorter pedal and shorter shaft
To keep from having to push the pedal really far down
I think the only way to make the clutch disengage faster would be to make the rod coming out of the master cylinder longer and the pedal shorter

Box = master cylinder
Black oval = plunger
Stick thing = plunger rod connected to pedal
Dotted line = location for plunger to be for "sweet spot"
( picture not even close to scale)
It's pretty simple longer pedal more leverage but more movement to get it all the way down
Shorter pedal quicker ..
The shaft shouldn't make much Much difference because you still have to push the plunger in the same distance but with the longer one would make your pedal closer to you
But the shorter one would let you make the bumps stop part shorter and keep the pedals all in one line more or less
( someone pease correct me If I'm wrong)
But I believe that the best way is to have a shorter pedal and shorter shaft
To keep from having to push the pedal really far down
Thread Starter
CF Veteran
Joined: Nov 2011
Posts: 7,387
Likes: 10
From: City of Trees, CA
Year: 93 2 door
Model: Cherokee
Engine: 4.0
great feedback guys. Im not sure now if I would really benefit and shift faster. but instead I could just hold down the gas at 2000-2500rpm maybe and feather the clutch. that way the clutch is basically my gas pedal, get what I'm sayin? I think thats what I was going for instead of faster shifting. but I could ride the clutch like that without a bump stop... Im still interested in trying.
and @buckshot500. I dont even have a jeep at the moment. but I will accept nothing other than a 91-95 with the ax15. so it will just be the stock trans and clutch in the future
this idea just occured to me and I posted it and was just wondering what everyone thought. just for the record I have no technical knowledge so it sounded possible to me
and @buckshot500. I dont even have a jeep at the moment. but I will accept nothing other than a 91-95 with the ax15. so it will just be the stock trans and clutch in the future
this idea just occured to me and I posted it and was just wondering what everyone thought. just for the record I have no technical knowledge so it sounded possible to me
Member
Joined: Apr 2011
Posts: 121
Likes: 0
From: Hendersonville, TN.
Year: 1990
Model: Cherokee
Engine: 4.0 I6
'Feathering' the clutch at 2000+ rpms will probly make it jerk really bad
Just saying cuz mine has a brand new clutch and I shift at 1500 ish and I can feel it when ever it engages
Just saying cuz mine has a brand new clutch and I shift at 1500 ish and I can feel it when ever it engages
Thread Starter
CF Veteran
Joined: Nov 2011
Posts: 7,387
Likes: 10
From: City of Trees, CA
Year: 93 2 door
Model: Cherokee
Engine: 4.0
I'm talking about strictly for crawling. but then again, I dont know 33's with 4.10 gears handle.
Member
Joined: Apr 2011
Posts: 121
Likes: 0
From: Hendersonville, TN.
Year: 1990
Model: Cherokee
Engine: 4.0 I6
Ah I'm saying 1500 on the street I actually just finished my ax15 swap and haven't got to test it out on the rocks but I'll be running a 4.88 or 4.56 with 39s and reduction box so my will be much different feel than yours ..


