Tremec TKX 5-Speed Conversion

[Kern Dog]

An issue that exists and has been resisting improvement is the clutch pedal feel.
The kit I used in 2021 used a Wilwood .75" master cylinder.

This one is the same size but a different brand.

Mine gives a pedal feel that is the same from top to the bottom. It literally feels like a newer car.

This OBP unit seems to give a mushy feel for the first third of travel, then it firms up for the rest. To me, that seems wrong.
We have bled the system multiple times....at least 10-12 sessions. The last half of those resulted in no change at all in pedal feel.

Also....My kit in 2021 was sent with standard DOT 4 fluid for the clutch master cylinder. The day we started bleeding the clutch, Rich had forgot to bring the fluid so we used the rest of the fluid that came with mine.

Then Rich came over another day with the bottle that came with the kit and it is labeled as being synthetic.

 

[Kern Dog]

Today I made a call to SST.
I told him of the concerns about pedal feel, fluid differences and.....that this throwout bearing only moves 5/8" at the most. The SST instructions state .910". That equates to just between 7/8" and 15/16".
The guy at SST said that there have been comments about that free play in the clutch pedal. I didn't press him on the matter but it seems that if the one in mine feels right, this one should too. If this were my car, I'd switch to a Wilwood unit.
The man said that the 5/8" of travel is enough for this bearing despite the instructions stating .910". I find that contradictory but he may be right. We started the car with the tires off the floor and Rich shifted through all the gears with no grinding. The clutch pedal was sitting even with the brake pedal for a better look. We thought the soft pedal was maybe an indicator that the clutch pedal needed more travel but after adjusting the linkage "turnbuckle" to allow the pedal to sit ridiculously high...

....... the pedal feel was the same. With that in mind, we might as well readjust the clutch pedal back down and be done with it.
Lastly, the SST man said that YES, they made the switch to using synthetic hydraulic fluid. They stuck by the DOT 4 though. There may still be some of the organic stuff in the system that we started with but I'm not sure since we have bled it so much with the new bottle. I don't know what drawbacks exist for mixing the two. It may be a moot point if Rich changes to a Wilwood unit since that will mean another round of bleeding the system.
Big day tomorrow. It should be ready for the first drive with the new setup!

I'd love to get feedback from other members about the pedal feel and free play that they have in their cars with the hydraulic clutch setup.

 

[HawkRod]

Some great details here - thanks for posting.

I have thought about switching to a hydraulic clutch a couple of times. With my old Borg & Beck clutch you needed Arnold Schwarzenegger in his prime to press the clutch pedal down. It was really bad. But then I replaced my clutch with a Centerforce diaphragm clutch that feels great, so I guess I don't have a great reason to switch out my clutch linkage from the manual system to a hydraulic one. Some of the issues you have had here make me more hesitant too.

Best of luck on the drive tomorrow - hopefully everything works smoothly!

 

[CoronetDarter]

Today could be the day the car rolls out of Greg shop on its own power. Just a few bullet points to tick off.
First, the core plug has to be reinstalled in the head. While the alternator is out I'm going to swap the fuel pump for a block off plate.
I researched brake fluids, and by law all DOT 3, 4, and 5.1 are compatible. Whether mineral or synthetic, they're all glycol based. We all know DOT 5 is incompatible with the other three.
Greg's call to SST is interesting. Last week I called SST asking about the same .910" CSC travel. Every prior time that I've called I talked to Chris, who comes off very knowledgeable and confident in his delivery. I believe that he's the narrator in their bellhousing runout video.
Last week I talked to Kyle, and he said the CSC should extend the entire .910". However, I didn't get a good feeling from the conversation. I could tell from the tone of his voice, or just a slight hesitation, that he wasn't completely confident in his reply. I suspect that Greg got a hold of Chris, not just because he gave the answer that I want to hear but because he provided anecdotal evidence that other owners had called about the same issue.
For now I'm going with the supplied OBP m/c just to test drive the car. I'll keep it for at least the 500 mile break-in period and then decide if I want to swap to the Wilwood. Summit sells the Wilwood m/c, a member here posted the part number earlier in this thread. It's a fairly common m/c with a .75" bore and 1.40" stroke.

 

[CoronetDarter]

Some great details here - thanks for posting.

I have thought about switching to a hydraulic clutch a couple of times. With my old Borg & Beck clutch you needed Arnold Schwarzenegger in his prime to press the clutch pedal down. It was really bad. But then I replaced my clutch with a Centerforce diaphragm clutch that feels great, so I guess I don't have a great reason to switch out my clutch linkage from the manual system to a hydraulic one. Some of the issues you have had here make me more hesitant too.

Best of luck on the drive tomorrow - hopefully everything works smoothly!

If your current setup works and the pedal pressure isn't giving you leg cramps, I agree there's no reason to convert to hydraulic. Aside from the installation, it's a pricey decision. The kits are around $600.

 

[Kern Dog]

One extremely valuable advantage is the clearance. If you have headers, the hydraulic line is like a spark plug wire in size. The stock cross shaft/Z bar and linkage rods all take up space and need occasional service.

I always forget about the "break in" cycle. I don't recall what my odometer read when I first drove with the 5 speed but I am LONG overdue for a fluid change.

 

[Kern Dog]

Here is a nugget that Rich found. I don’t know if my instructions stated this:

This pertains to the .910 travel of the throw out bearing. “Slightly over 7/8” stroke MINUS the bearing cushion, not total stroke.
Closer:

Backing up a bit, number 3 on the list does read “Low resistance for initial travel….increasing at 1/3 of full stroke and remaining approximately constant through full travel…”
Yeah… that is exactly what we got. Still, we still bled the system again. It does feel better and Rich is happy with it.
Did he drive it today?
I’ll let him tell the story.
Good news though….

 

[68 Sport Satellite]

Another thing to remember (I don't know if this is true for a hydraulic clutch system, but they both use throwout bearings, so it could be) - from my experience in changing out mechanical clutches and throwout bearings in my own 1967 chevy, the first few drives the clutch pedal effort is fairly easy and light and depresses smooth like butter. After about 80-100 shift cycles, the pedal starts to firm up to how it will normally feel for most of its life. Not sure if this is from the throwout bearing grease distributing out or the clutch spline fingers settling in or what. I've often wished the mechanical clutch pedal feel could stay feeling the way it feels when brand new with fresh grease.

I drove Greg's car - the Wilwood hydraulic clutch feel was great, both pedal effort and grab. The only thing I didn't like is the side kick on the pistol grip that I experienced when in first gear and clutching to shift (3rd to 2nd as I recall). It was quite noticeable and Greg knows what I'm talking about. I don't recall feeling such an issue in driving Dennis' 69 RT or Meep-Meep's 69 RR. I'll be curious to hear if Rich's car has a similar shifting feel as Greg's or if that is absent. Hopefully the latter.

 

[CoronetDarter]

Before we got to the final stages of the clutch assembly, there was still a hole in the passenger side head. I got a core plug kit from 440 Source. The kit came with four 1" plugs and four 1 1/4" plugs. The diameter of the core hole is slightly larger than 1", more like 1.02". The replacement plugs pushed into the head with no resistance. So while I pulled off the fuel pump to swap in the block off plate, Greg took off searching for a core plug. He was able to find one that measured 1.06 - 1.07. For insurance, he also picked up a rubber expansion plug. The 1.06 core plug was too big so we wound up installing the expansion plug.

Not the most elegant choice, but it works and it's mostly hidden behind the alternator. Which brought up another unintended consequence. The threaded stud on the expansion plug interfered with the back of the alternator at full adjustment. Greg took out his cutoff wheel and make short work of the stud. BTW, that's a 1/0 negative cable going to the chassis. No pics, but the alternator installed with no drama.

 

[CoronetDarter]

Back to the clutch. When we left off last weekend, the CSC travel was well below the .910" or 7/8" travel that was spec'd in the instructions. Plus the pedal felt mushy for the first 1/3 of travel.
As Greg posted earlier, the Final Testing section of the instructions acknowledges the CSC doesn't travel the entire 7/8", and the instructions clearly state a "low resistance for first 1/3 of pedal travel". WTF? My Dart and Greg's Charger aren't limp dicked for the first part of the pedal travel.
So we gave it another shot at bleeding the m/c. This time we took a different tact: I pumped the pedal 7 or 8 times and then released the pedal. Then Greg opened the bleeder valve. Some air spurted out, followed by a steady stream of brake fluid, at which time Greg tightened the valve. The feel of the pedal changed dramatically; the mushiness was gone. We followed the procedure two more times and the pedal now has resistance through the entire travel. Last weekend we bled the m/c the same way you would a brake m/c; this week we switched it up. Was that the reason? We're not sure, but the Mopar gods were smiling down on us, so we're good.

 

[CoronetDarter]

Wait, there's a good reason why Greg is doing a plumber's impression in the trunk of my car.

One of the last things to do was bolt up the exhaust hangers; Greg was in the trunk with a box wrench giving resistance while I torqued down the nut from underneath. He has an infinite amount more dexterity than I do.

Inspection plate installed, bottom end buttoned up. Some of the last underneath shots of the install.


Time for the big reveal, and I can't post the vid. Greg took two video's of me driving the car in his back yard, and I can't upload them. I'll be back...

 

[68 Sport Satellite]

Nice work guys! That's awesome your bleeding procedure remedied the pedal feel issue.

 

[Kern Dog]

A good portion of the luck that I have just comes my way by accident.
I stumble through a project and ideas just come to me or good luck falls into my lap.
Sure, I get obstacles like anyone but I try to avoid dwelling on them.
The clutch pedal feel is one of those things. Cracking the bleeder screw, it didn't actually spurt out air so much as the fluid dripped like a pulse where there was a momentary space between drips, then turned into an even stream. I just closed off the bleeder screw once it was a stream. I'm new to this stuff so I was just trying something without knowing if it would help. I hope that this idea helps out someone else that faces the same issue.
In addition:
I'd like to make a list of some of the discrepancies between conventional knowledge, the SST instructions and their over-the-phone advice VS how the real world installations actually get done. There may be things the SST crew doesn't know are a problem unless people chime in.
I will say that their instructions are far better than a Vintage Air A/C system. Their instructions might as well be written in Japanese with illustrations done with Crayola crayons.

 

[Charlie Brown]

A good portion of the luck that I have just comes my way by accident.
I stumble through a project and ideas just come to me or good luck falls into my lap.
Sure, I get obstacles like anyone but I try to avoid dwelling on them.
The clutch pedal feel is one of those things. Cracking the bleeder screw, it didn't actually spurt out air so much as the fluid dripped like a pulse where there was a momentary space between drips, then turned into an even stream. I just closed off the bleeder screw once it was a stream. I'm new to this stuff so I was just trying something without knowing if it would help. I hope that this idea helps out someone else that faces the same issue.
In addition:
I'd like to make a list of some of the discrepancies between conventional knowledge, the SST instructions and their over-the-phone advice VS how the real world installations actually get done. There may be things the SST crew doesn't know are a problem unless people chime in.
I will say that their instructions are far better than a Vintage Air A/C system. Their instructions might as well be written in Japanese with illustrations done with Crayola crayons.

I'm a big believer that people make their own luck. It's no coincidence that your "luck" falls into your lap Greg - it's your attention to detail and persistence that pays off. The other kind of luck is winning a lottery.

 

[ckessel]

Since the heads are made way west of here across the Pacific, I'll bet the freeze plugs are metric. 1.0236" = 26mm.
Greg doesn't look like a plumber, pants are pulled up and no butt crack.

 

[HawkRod]

Wait, there's a good reason why Greg is doing a plumber's impression in the trunk of my car.

If both of you were in the trunk, I'd get worried...

Nice work on finishing things up!

 

[Kern Dog]

Since the heads are made way west of here across the Pacific, I'll bet the freeze plugs are metric. 1.0236" = 26mm.
Greg doesn't look like a plumber, pants are pulled up and no butt crack.

This time of year, I really try to avoid *** crack exposure.
I really need to find some shirts that are LONGER. Too many shirts pull up past the waistband when your arms go up over your head, leaving the *** crack exposed.
Summer time *** crack exposure is uncomfortable to others but Winter time *** crack exposure is uncomfortable to the man himself.

 

[1 Wild R/T]

This time of year, I really try to avoid *** crack exposure.
I really need to find some shirts that are LONGER. Too many shirts pull up past the waistband when your arms go up over your head, leaving the *** crack exposed.
Summer time *** crack exposure is uncomfortable to others but Winter time *** crack exposure is uncomfortable to the man

Are you familiar with the acronym TMI??? Well, you should be...

 

[hunt2elk]

If both of you were in the trunk, I'd get worried...

Nice work on finishing things up!

Lol. If you knew Rich, you would know that wouldn't be possible.

 

[HawkRod]

Lol. If you knew Rich, you would know that wouldn't be possible.

Oh, I know Rich well - he helped ship my 70 Road Runner in 2015 and he was also an "official destination" for my 2022 cross country trip! Yes, Rich in the trunk as well would make things very close, hence my comment.

I'm just glad to call the man a good friend - you wouldn't want to be on the receiving end of a pissed off Rich in a back alley!