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Slave cylinder overextended?? 3800 w/F40 by dnthmn87
Started on: 08-25-2021 05:11 AM
Replies: 5 (115 views)
Last post by: fieroguru on 09-08-2021 08:25 PM
dnthmn87
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Report this Post08-25-2021 05:11 AM Click Here to See the Profile for dnthmn87Click Here to Email dnthmn87Send a Private Message to dnthmn87Edit/Delete MessageReply w/QuoteDirect Link to This Post
I found a new old stock F40 transmission on the local classifieds. It has never been used and came with a 6 puck clutch and flywheel, which weren't used either but it seems that at least the transmission was left out in the weather a fair bit. I installed this setup on my 2006 Grand prix and started to bleed the clutch master cylinder and slave, but was quickly disappointed when the clutch pedal gave way when still trying to bleed the system. That was followed by a steady stream of fluid coming out the bottom of the trans. So either the slave cylinder gave way because it was 15 years old but never used??? Or possibly the slave cylinder had to overextend because my flywheel is to thin? Or was there supposed to be some spacer between the throwout bearing and clutch fingers? Any suggestions are welcome. I'm hoping to drop the trans this thursday night and I have a new slave on its way to install. But maybe I need to do some measuring first??

Thanks

Dan
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fieroguru
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Report this Post08-25-2021 08:15 AM Click Here to See the Profile for fieroguruSend a Private Message to fieroguruEdit/Delete MessageReply w/QuoteDirect Link to This Post
Never install a HTOB transmission without measuring the stack height to the fingers and the range of motion for the HTOB. Lots of people have over extended them due to not measuring first.

Specs solution for the F40/3800 was based on a full thickness Camaro flywheel, clutch disk with a flipped hub (to increase spline engagement), a pressure plate with altered finger placement, and a HTOB spacer. Far from an ideal setup and easy to accidentally swap out any of the 4 parts for similar but not the same and run into issues.

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dnthmn87
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Report this Post08-25-2021 03:31 PM Click Here to See the Profile for dnthmn87Click Here to Email dnthmn87Send a Private Message to dnthmn87Edit/Delete MessageReply w/QuoteDirect Link to This Post
Thanks for responding Fieroguru. That's all new info to me, guess I lacked the research. Another piece of the puzzle is that I originally installed a 5 speed 282 from an 89 Grand Prix, and am still using that master cylinder. Not sure if that displaces too much fluid or not. But I definitely need get an HTOB spacer, and didn't flip the clutch around for better spline engagement. I believe it is a stock camaro flywheel with the spec clutch. Where do you recommend getting the spacer? Is the air gap the same as stack height? Just watched a video on measuring the air gap (working manual transmissions is new to me).

[This message has been edited by dnthmn87 (edited 08-25-2021).]

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dnthmn87
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Report this Post09-02-2021 05:29 PM Click Here to See the Profile for dnthmn87Click Here to Email dnthmn87Send a Private Message to dnthmn87Edit/Delete MessageReply w/QuoteDirect Link to This Post
So I got the transmission out last night and measured from the clutch fingers to the block, 3'' exactly. Bellhousing to TOB was 2'' 7/8 with the slave cylinder compressed with the bleeder installed and open. So 1/8" of an inch is actually ideal, right? Could the seal of the original one just have just blown out because it was 15 years old and sat out in the sun for a couple years?
note, my throwout bearing didn't compress even half as much as the one in the video that I watched on how to do this, but it was a different transmission. But it does compress at least 1/4'', using the new slave.
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dnthmn87
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Report this Post09-08-2021 03:09 AM Click Here to See the Profile for dnthmn87Click Here to Email dnthmn87Send a Private Message to dnthmn87Edit/Delete MessageReply w/QuoteDirect Link to This Post
Forget my last post, it is 3.5 inches from the bell housing mating service to the compressed slave cylinder, only 3” from the pressure plate fingers to the block, so I’ve got 1/2”… I’ve found 1/4” spacer so hopefully that’ll be good enough 🤷‍♂️.
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Report this Post09-08-2021 08:25 PM Click Here to See the Profile for fieroguruSend a Private Message to fieroguruEdit/Delete MessageReply w/QuoteDirect Link to This Post
A stock F40 HTOB has about 0.90" of available travel. You want about 25% of this to be for wear (gap between pressure plate fingers and fully compressed HTOB) and 75% of this for travel to release the clutch.

You want something around 0.225" for wear so you have about .675" for clutch release travel. Having 0.5" for wear is a bad thing.
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