Clutch peddle assist

Joined
Nov 6, 2013
Messages
734
Visit site
Anyone have knowledge or experience with clutch peddle assist?
I have just started looking and found some vacuum boosters but not much on application or performance.
 
Joined
Nov 6, 2013
Messages
734
Visit site
I can handle the GM clutch alright but was thinking if my wife had to do any amount of driving.
Dropping the trans and t case is on my to do list and someone here mentioned that center force had an easy peddle.
Just thinking of things to keep me busy and off the streets.
 

65swb45

Elder Statesman
Supporting Vendor
Joined
Apr 14, 2004
Messages
30,064
Location
818-953-9230
Website
www.marksoffroad.net
The diaphragm pressure plate is easier to operate than the three finger. And since some of the 3-finger parts have become obsolete, a swap during trans/transfer maintenance is not necessarily a bad idea.

I still wheel my junk a lot, and I prefer the heavier rotating mass of the older flywheel pressure plate combo.
 
Joined
Aug 21, 2006
Messages
2,011
Location
Kennesaw, GA
Visit site
My '86 Canadian spec BJ70 has a clutch factory booster. It yields pedal pressure that feels similar to that of my '81 FJ40 (no clutch booster). After the 70 sits for long periods and the vacuum has bled off, I have experienced unaided clutch pedal pressure for my 3B. The resulting pedal pressure is noticeably more, enough that stop-n-go traffic could be unpleasant. Consequently, I consider it a good feature from Toyota but a pain in the arse to replace. [space and access limitations, getting effectively a specialty component from Toyota]

Additionally, the boost level to aid in clutch pedal pressure is probably significantly less than that needed for braking. This results in fairly small size of the clutch booster. My projection (concern) is it might be difficult to find and size match an alternate booster (brake booster) to deliver the desired performance for clutch pedal feel and fit in the space available (i.e., nested close to the brake booster, steering column & inner fender). As such, could a pure mechanical solution be easier to create a custom solution? (such as the use of stiffer/stronger springs and longer moment arm length to gain mechanical advantage to reduce required pedal pressure?)

Good luck.
 
Joined
Nov 6, 2013
Messages
734
Visit site
My '86 Canadian spec BJ70 has a clutch factory booster. It yields pedal pressure that feels similar to that of my '81 FJ40 (no clutch booster). After the 70 sits for long periods and the vacuum has bled off, I have experienced unaided clutch pedal pressure for my 3B. The resulting pedal pressure is noticeably more, enough that stop-n-go traffic could be unpleasant. Consequently, I consider it a good feature from Toyota but a pain in the arse to replace. [space and access limitations, getting effectively a specialty component from Toyota]

Additionally, the boost level to aid in clutch pedal pressure is probably significantly less than that needed for braking. This results in fairly small size of the clutch booster. My projection (concern) is it might be difficult to find and size match an alternate booster (brake booster) to deliver the desired performance for clutch pedal feel and fit in the space available (i.e., nested close to the brake booster, steering column & inner fender). As such, could a pure mechanical solution be easier to create a custom solution? (such as the use of stiffer/stronger springs and longer moment arm length to gain mechanical advantage to reduce required pedal pressure?)

Good luck.
moment arm? Is that the clutch peddle arm? Tried lengthening the arm for more leverage but felt awkward.

My wife has driven the Toy in the past but broke her hip a few years ago and it has never been the same since but has clutched since the surgery.

Thanks for the input.
 
Joined
Feb 3, 2020
Messages
405
Location
Stanwood, WA
Visit site
I have a Centerforce dual friction in my big block chevelle. It is a very light pedal, but still get no slippage with the 550+ hp I have in that motor. If you’re dropping trans anyway, maybe it’s worth a try?
 
Joined
Feb 3, 2020
Messages
405
Location
Stanwood, WA
Visit site
moment arm? Is that the clutch peddle arm? Tried lengthening the arm for more leverage but felt awkward.

My wife has driven the Toy in the past but broke her hip a few years ago and it has never been the same since but has clutched since the surgery.

Thanks for the input.
The issue I’ve seen in the past with longer clutch forks, linkages, etc. to gain leverage is that you are losing throw to disengage the clutch pressure plate. So often to correct that, you'd then need to add travel to the clutch pedal itself or somewhere else in the chain.
What trans is behind the chevy 350?
 
Joined
Aug 21, 2006
Messages
2,011
Location
Kennesaw, GA
Visit site
moment arm? Is that the clutch peddle arm? Tried lengthening the arm for more leverage but felt awkward.

My wife has driven the Toy in the past but broke her hip a few years ago and it has never been the same since but has clutched since the surgery.

Thanks for the input.

Effectively yes changing the length of the peddle arm could be attempted. The info in the prior posts appear to imply that this might be a custom installation where changes to pedal lengths and/or springs might be utilized to produce the pedal force desired. As Skreddy identified; functional and ergometric aspects will need to be addressed in a custom installation.
 

65swb45

Elder Statesman
Supporting Vendor
Joined
Apr 14, 2004
Messages
30,064
Location
818-953-9230
Website
www.marksoffroad.net
My '86 Canadian spec BJ70 has a clutch factory booster. It yields pedal pressure that feels similar to that of my '81 FJ40 (no clutch booster). After the 70 sits for long periods and the vacuum has bled off, I have experienced unaided clutch pedal pressure for my 3B. The resulting pedal pressure is noticeably more, enough that stop-n-go traffic could be unpleasant. Consequently, I consider it a good feature from Toyota but a pain in the arse to replace. [space and access limitations, getting effectively a specialty component from Toyota]

Additionally, the boost level to aid in clutch pedal pressure is probably significantly less than that needed for braking. This results in fairly small size of the clutch booster. My projection (concern) is it might be difficult to find and size match an alternate booster (brake booster) to deliver the desired performance for clutch pedal feel and fit in the space available (i.e., nested close to the brake booster, steering column & inner fender). As such, could a pure mechanical solution be easier to create a custom solution? (such as the use of stiffer/stronger springs and longer moment arm length to gain mechanical advantage to reduce required pedal pressure?)

Good luck.
Thanks for chiming in Larry.

I think there may be a second, as yet undiscussed, consideration. Is it JUST pressure, or is there also a range of motion issue for the driver. The friend that gave me the Karma Cruiser had both, so sorting out the pressure issues wasn’t going to be enough.
 
Joined
Nov 6, 2013
Messages
734
Visit site
There is an extra notch on the throw out fork but using it cuts the peddle travel losing what little travel there already is.
The original six gave up the ghost just north of 200K miles back in 1984.
Money was tight so a 350 was cheaper.
Used a cast iron bell and kept the crash box.
At the time I had no real experience and minimal input on how to go about the conversion.
Used an AA kit and all in all compared to what I have seen since I did a pretty good job.
Had some issues with clutch fully disengaging the stock Chevy clutch but with some tinkering managed to make it work all these years.
The rig has been pretty reliable but have been threatening to address the leaky trans and case so for sure am going to put in new clutch, P plate and throw out brng.
I have thought about selling my Toy but the wife is adamant about not so was just thinking of ways to make it easier for her in our old age.
I have a knack for making thing more complicated than need be so probably should leave well enough alone.
 

Users who are viewing this thread

Top Bottom