Hurst Driveline hydraulic throw out bearing

[1934chevycoupe]

Couldn't find any info on here, so I'll start a new thread. Bought all my stuff from Hurst Driveline Conversions about 6-7 years ago. Finally got my bell housing issues all straightened out, and ready to put the Magnum in, and realized i need to check slave cylinder cushion? Video at Silver Sport Trans. says to measure from the outer bell to the pressure plate fingers = X. Measure from the trans mating surface to the collapsed throwout bearing surface = Y. X - Y should be between 1/8" and 3/8". I'm right at 3/8". Tick performance says it should be .125-.200. After messaging Jody @ Jody's Transmissions, he uses McLeod and Tilton which are setup differently. Hurst manual says nothing on the subject. Throw it in and go. Anyone use Hurst or recognize this style and have an answer? Thanks

 

[1934chevycoupe]

i've discovered it's the oem 98-02 Camaro - Firebird -LS1 bearing. apparently Dorman, Luk and GM make this style.

 

[biker]

I can't imagine that it would just be pop it in and go. With a hydraulic slave cylinder as opposed to factory linkage, there is no way to adjust for free play.
The Silver Sport bearing I used is designed to stay in contact with the pressure plate diaphragm spring fingers and needs to have the "cushion" you mentioned above. Otherwise, it will bottom out on the fjngers, or it will over-extend at full stroke. I had to add a 1/4" spacer between engine and trans to get the right measurement.

I know some systems have an option that goes in line with the clutch hydraulic line and allows you to adjust pedal height. Don't know if it adjusts free play,

In any event, you do have good clearance. I did a quick search too, and while there wasn't any specific info, everything I read did mention having a free-play gap for the bearing.

Maybe a quick call to Hurst would get you the right info. They may have changed their bearing design since you bought yours.

 

[1934chevycoupe]

I can't imagine that it would just be pop it in and go. With a hydraulic slave cylinder as opposed to factory linkage, there is no way to adjust for free play.
The Silver Sport bearing I used is designed to stay in contact with the pressure plate diaphragm spring fingers and needs to have the "cushion" you mentioned above. Otherwise, it will bottom out on the fjngers, or it will over-extend at full stroke. I had to add a 1/4" spacer between engine and trans to get the right measurement.

I know some systems have an option that goes in line with the clutch hydraulic line and allows you to adjust pedal height. Don't know if it adjusts free play,

In any event, you do have good clearance. I did a quick search too, and while there wasn't any specific info, everything I read did mention having a free-play gap for the bearing.

Maybe a quick call to Hurst would get you the right info. They may have changed their bearing design since you bought yours.

i'm wondering since Holley took over Hurst, if there is anyone there that would have knowledge of what i have. i thought i'd call Silver Sport tomorrow, and see what they have to say. at the least, if i put in shims that get me down to 1/8" cushion, i'd be in compliance w/ both.

 

[biker]

i'm wondering since Holley took over Hurst, if there is anyone there that would have knowledge of what i have. i thought i'd call Silver Sport tomorrow, and see what they have to say. at the least, if i put in shims that get me down to 1/8" cushion, i'd be in compliance w/ both.

Good plan.

 

[1934chevycoupe]

spoke w/ Tick Performance this morning, and he said to get as close to 1/8th or .125 as possible. ordered their .055 & .180 shims, which will put me at .140 cushion. just a shade over the 1/8th ideal.

 

[goshox70]

spoke w/ Tick Performance this morning, and he said to get as close to 1/8th or .125 as possible. ordered their .055 & .180 shims, which will put me at .140 cushion. just a shade over the 1/8th ideal.

This topic is interesting to me because I am in a similar but different situation. I bought by 79Z a little over a year ago and it already had been converted from auto to manual with the Hurst Driveline conversion (per the PO).

It has always leaked a very small amount of transmission fluid from the bell housing so I assume I need a new front seal. I just replaced the turned down before the axle exhaust with a whole new setup from Pypes routed to the back and now I can actually hear myself think inside the car and I am noticing a whirring noise when I engage the clutch to shift. Thinking it *might* be the throwout bearing but since I haven't pulled the transmission yet and I can't find any info on the conversion kit anymore I am not really sure what I have in there. I am assuming it will be the same as you have (gm/Luk hydrallic slave).

In my research preparing to fix this I ran across some literature from Tilton that says the clutch pedal should have a stop behind it to keep it from going all the way to the floor and overextending the slave/over-compressing the diaphragm spring fingers. I can't find anything about this related to the GM style slave but I don't have a pedal stop in my car and it bottoms out on the floor board if I don't pull up short. It feels like there is a lot of unnecessary throw in the pedal to me but I am not sure if its "bad" or just wasteful.

So, did Tick mention anything to you about adjusting your clutch pedal stop for your install? Does your install info mention anything about it?

Curious if this is somehow slave design dependent or if mine wasn't done right in the beginning. Also possible I am way overthinking this.....

 

[1934chevycoupe]

This topic is interesting to me because I am in a similar but different situation. I bought by 79Z a little over a year ago and it already had been converted from auto to manual with the Hurst Driveline conversion (per the PO).

It has always leaked a very small amount of transmission fluid from the bell housing so I assume I need a new front seal. I just replaced the turned down before the axle exhaust with a whole new setup from Pypes routed to the back and now I can actually hear myself think inside the car and I am noticing a whirring noise when I engage the clutch to shift. Thinking it *might* be the throwout bearing but since I haven't pulled the transmission yet and I can't find any info on the conversion kit anymore I am not really sure what I have in there. I am assuming it will be the same as you have (gm/Luk hydrallic slave).

In my research preparing to fix this I ran across some literature from Tilton that says the clutch pedal should have a stop behind it to keep it from going all the way to the floor and overextending the slave/over-compressing the diaphragm spring fingers. I can't find anything about this related to the GM style slave but I don't have a pedal stop in my car and it bottoms out on the floor board if I don't pull up short. It feels like there is a lot of unnecessary throw in the pedal to me but I am not sure if its "bad" or just wasteful.

So, did Tick mention anything to you about adjusting your clutch pedal stop for your install? Does your install info mention anything about it?

Curious if this is somehow slave design dependent or if mine wasn't done right in the beginning. Also possible I am way overthinking this.....

Tick didn't say anything about pedal stop, but i think i have also read about it being for what you said, not to over extend the diaphragm. That i believe is also the reason for checking the cushion of the throwout bearing.

Hursts manual, in hindsight, leaves a lot to be desired. They didn't mention anything about checking runout, and nothing about checking the throwout bearing cushion. And basically included all OEM parts to go w/ the Magnum to keep the cost down. I'm realizing all my parts are based on 98-02 Camaro-Firebird OEM replacement parts. Live and learn. You probably have the same slave-throwout i do, GM part # 24264182. I modified it, and removed the bleeder valve, and installed my own 18" 4AN line to a speed bleeder. I saw a few kits w/ 4' lines, which i think are intended to put the bleeder in the engine bay, but i thought this would be cleaner. Let me go take a pic.

 

[1934chevycoupe]

This topic is interesting to me because I am in a similar but different situation. I bought by 79Z a little over a year ago and it already had been converted from auto to manual with the Hurst Driveline conversion (per the PO).

It has always leaked a very small amount of transmission fluid from the bell housing so I assume I need a new front seal. I just replaced the turned down before the axle exhaust with a whole new setup from Pypes routed to the back and now I can actually hear myself think inside the car and I am noticing a whirring noise when I engage the clutch to shift. Thinking it *might* be the throwout bearing but since I haven't pulled the transmission yet and I can't find any info on the conversion kit anymore I am not really sure what I have in there. I am assuming it will be the same as you have (gm/Luk hydrallic slave).

In my research preparing to fix this I ran across some literature from Tilton that says the clutch pedal should have a stop behind it to keep it from going all the way to the floor and overextending the slave/over-compressing the diaphragm spring fingers. I can't find anything about this related to the GM style slave but I don't have a pedal stop in my car and it bottoms out on the floor board if I don't pull up short. It feels like there is a lot of unnecessary throw in the pedal to me but I am not sure if its "bad" or just wasteful.

So, did Tick mention anything to you about adjusting your clutch pedal stop for your install? Does your install info mention anything about it?

Curious if this is somehow slave design dependent or if mine wasn't done right in the beginning. Also possible I am way overthinking this.....

Tick will probably be able to tell you how to know how to adjust the stop. Seem to be knowledgeable and willing to help. I also read on the LS1Tech forum where they were helping people w/ the throwout cushion measurement. Their # is 336-719-0599

 

[goshox70]

Tick will probably be able to tell you how to know how to adjust the stop. Seem to be knowledgeable and willing to help. I also read on the LS1Tech forum where they were helping people w/ the throwout cushion measurement. Their # is 336-719-0599

Thanks! In my google exploration I did find the link below that discusses the GM slave with a Magnum in a gen2 fbody. It seems to have lots of useful info. You may already have all this figured or found it for yourself but it specifically talks about setting the cushion and using Tick spacers. Sounds like the factory slave configuration is a little different than the aftermarket ones in that it is designed to lightly rest on the clutch fingers rather than get thrown back a slight amount (like a brake pad) on its own. The article mentions making sure you compress the spring that pushes the bearing out before making your clearance measurements.

He also changed out the bleed connection and routed it out of the housing. That is a great idea and I am definitely doing that when I tear mine down.

https://www.modsandrods.tv/2020/02/...-a-2nd-gen-firebird-trans-am-with-pontiac-v8/