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View Full Version : Transmission 5-Speed Why doesn't the clutch line run directly?



Emit
08-20-2024, 07:41 AM
Why doesn't the clutch hydraulic hose go directly from the master to the slave cylinder? What is the purpose of the hard line attached to the transmission? Was it to assist in assembly/repair?

Would it not be better going directly, thus eliminating a connection?

I have the engine out and to me it makes sense to run a flexible line the whole way

dn010
08-20-2024, 09:02 AM
Since the crossover pipe originally runs directly above the line, I'd assume they did it that way so it's fixed and can't move to touch the pipe and also so the inside of the flexible line doesn't melt from the exhaust heat.

David T
08-20-2024, 09:42 AM
My guess is it aided them in assembling the car. Like the pipe that runs under the intake manifold.

WHO1DMC
08-20-2024, 10:12 AM
Since the crossover pipe originally runs directly above the line, I'd assume they did it that way so it's fixed and can't move to touch the pipe and also so the inside of the flexible line doesn't melt from the exhaust heat.
I think it was definitely to protect the original line from the heat. Just this weekend I was at a show and this guy asked if I lost my clutch when running the A/C. I confusingly said no. He explained that a friend that had one when they were new and was having clutch problems with the A/C being on. There fix was to insulat the clutch line from the A/C line. So if they had the improved line like we do now they might not have used the hard pipe. I'm not a engineer so that is just a guess. But as I write this I'm thinking it's better to have a pipe that is bent to go around a problem area than a flexible one that will need clamps that could come loose.

I'm running the new line so that's why it took me a little bit to think about this problem he was talking about. As he kept explaining it was like yup I know exactly what you're saying. When you don't have the problem you totally forget there was once this this problem.

Dave B.

David T
08-20-2024, 10:54 PM
I think it was definitely to protect the original line from the heat. Just this weekend I was at a show and this guy asked if I lost my clutch when running the A/C. I confusingly said no. He explained that a friend that had one when they were new and was having clutch problems with the A/C being on. There fix was to insulat the clutch line from the A/C line. So if they had the improved line like we do now they might not have used the hard pipe. I'm not a engineer so that is just a guess. But as I write this I'm thinking it's better to have a pipe that is bent to go around a problem area than a flexible one that will need clamps that could come loose.

I'm running the new line so that's why it took me a little bit to think about this problem he was talking about. As he kept explaining it was like yup I know exactly what you're saying. When you don't have the problem you totally forget there was once this this problem.

Dave B.

The original hose was a plastic hose and when it got hot it would expand when you put pressure on it so you lost a lot of motion on the clutch. In Lotus World they call it red hose syndrome. Early on the vendors offered S/S braided hoses that don't expand when they get hot. Some vendors offer a longer hose so you don't need to use the metal line. Anyone still using the plastic hose should replace it with the S/S braided one. If you have the plastic one and you force your shifts, you will damage a roll pin inside the transmission and/or break the pivot bolt in the shift linkage. Either way you can be stranded and have to get towed. It is also important to flush and bleed the clutch when you do the brakes at least every 2 years. If the brake fluid gets old and full of moisture it will boil at much lower temperatures besides becoming acidic and pitting the cylinders making them leak.

82DMC12
08-21-2024, 11:12 AM
I replaced my hard pipe and formerly stainless braided section the slave, with a one-piece stainless braided line from DPI. There's a stay that supports it to the top of the transmission, otherwise it runs freely and zip tied along the driver side of the frame. Works perfectly. Clutch engagement remains about halfway in pedal travel. No regrets.

Helirich
08-21-2024, 12:46 PM
I replaced my hard pipe and formerly stainless braided section the slave, with a one-piece stainless braided line from DPI. There's a stay that supports it to the top of the transmission, otherwise it runs freely and zip tied along the driver side of the frame. Works perfectly. Clutch engagement remains about halfway in pedal travel. No regrets.

Are you saying that halfway through your pedal travel you can shift in to any gear without grinding? How far off the floor would you say you can do this? On mine, it?s like 1/2?, maybe less. I pretty much always push it to the floor. Certainly if I?m stopped. If my thick carpet gets slid forward and blocks the pedal travel a little, it won?t completely disengage.

dn010
08-21-2024, 12:51 PM
Are you using an adjustable clevis?


I replaced my hard pipe and formerly stainless braided section the slave, with a one-piece stainless braided line from DPI. There's a stay that supports it to the top of the transmission, otherwise it runs freely and zip tied along the driver side of the frame. Works perfectly. Clutch engagement remains about halfway in pedal travel. No regrets.

82DMC12
08-21-2024, 12:52 PM
Are you saying that halfway through your pedal travel you can shift in to any gear without grinding? How far off the floor would you say you can do this? On mine, it?s like 1/2?, maybe less. I pretty much always push it to the floor. Certainly if I?m stopped. If my thick carpet gets slid forward and blocks the pedal travel a little, it won?t completely disengage.

I always push the pedal to the floor when shifting out of muscle memory and caution, but if I am at a stop sign, my clutch starts to grab and pull me forward about halfway upward in the pedal travel when letting up on the pedal. So, I probably could shift gears 2/3 of the way through the stroke but haven't tried it.

My car has always been like that, and this is the third clutch I've had in the car. First one was probably original which was replaced with a Centerforce under my ownership around 2003. Then I just replaced that one with a Valeo from Toby last year. All behaved the same.

The point of "grab" is related to the step on the fly wheel, the lack of air in the clutch line, and assuming the pedal itself is in factory condition and not bent or using an adjustable clutch link.

Interestingly I just helped another owner put a new clutch in last weekend. He got the flywheel machined to 0.018" step and his pedal grabs about an inch off the floor. He is going to try bleeding the clutch and see if it gets a bit more comfortable to use.

82DMC12
08-21-2024, 01:00 PM
Are you using an adjustable clevis?

I'd have to check, I honestly don't remember. If I do, it was installed before I got the car, however my clutch pedal and brake pedal are at the same height, and the instructions for the adjustable linkage says the clutch pedal will be about 3/4" higher than the brake after correct adjustment.

r00b
08-21-2024, 04:57 PM
I Installed this master https://www.autozone.com/drivetrain/clutch-master-cylinder/p/duralast-clutch-master-cylinder-11958/733832_0_0
with the fork from this master https://www.amazon.com/dp/B000CAVUKC

I hacked the threaded portion in half, it moved the clutch engagement into the first half of the pedal travel. If you are having problems with your engagement being to close to the floor this will probably fix that for you.

82DMC12
08-21-2024, 09:09 PM
double checked and confirmed I do not have the adjustable clutch linkage. My step was machined to 0.018" last year when I had the engine out and put a new Valeo clutch in.

dn010
08-22-2024, 09:47 AM
I had mine cut to .020. I also have a new Valeo clutch kit. I'm just waiting on some engine parts from Sweden to arrive and then I can put the engine in and let you know how mine is. I used to have a lot of free-play (no adjustable clevis either), we'll see what happens.

WHO1DMC
08-22-2024, 11:04 AM
I had mine cut to .020. I also have a new Valeo clutch kit. I'm just waiting on some engine parts from Sweden to arrive and then I can put the engine in and let you know how mine is. I used to have a lot of free-play (no adjustable clevis either), we'll see what happens.

I also put in a new clutch last spring and cut mine at .020 because that is what Mike at Delorean Midwest will tell you.



Dave B.

dmcman73
08-22-2024, 11:07 AM
I always push the pedal to the floor when shifting out of muscle memory and caution, but if I am at a stop sign, my clutch starts to grab and pull me forward about halfway upward in the pedal travel when letting up on the pedal. So, I probably could shift gears 2/3 of the way through the stroke but haven't tried it.

My car has always been like that, and this is the third clutch I've had in the car. First one was probably original which was replaced with a Centerforce under my ownership around 2003. Then I just replaced that one with a Valeo from Toby last year. All behaved the same.

The point of "grab" is related to the step on the fly wheel, the lack of air in the clutch line, and assuming the pedal itself is in factory condition and not bent or using an adjustable clutch link.

Interestingly I just helped another owner put a new clutch in last weekend. He got the flywheel machined to 0.018" step and his pedal grabs about an inch off the floor. He is going to try bleeding the clutch and see if it gets a bit more comfortable to use.

My car is the same way. The half way point is where the clutch begins to grab/release and I always press all the way to the floor before shifting out of habit.

If anyone has the adjustable linkage, just be sure you do not adjust it too far out otherwise you'll have a new issue where the fingers on the clutch pressure plate will be pushed to far inwards and start to grind.

Helirich
08-22-2024, 12:40 PM
Are you saying that halfway through your pedal travel you can shift in to any gear without grinding? How far off the floor would you say you can do this? On mine, it?s like 1/2?, maybe less. I pretty much always push it to the floor. Certainly if I?m stopped. If my thick carpet gets slid forward and blocks the pedal travel a little, it won?t completely disengage.

I have to repost this because this forum always inserts ? For quotation marks. To clarify, my clutch will not disengage till 1/2 inch off the floor.