Clutch help

[ViperGeorge]

I have a 9L extreme with an Nth Moto clutch. When I start the car with the clutch pedal fully depressed and car in 1st or reverse the car moves. The starter is moving the car as though the clutch is not fully disengaged. Clutch still engages at the same spot when driving. Thoughts?

[Steve M]

With the car running and the transmission in first gear, rev it up to 5-6k RPMs. Does the car move at all?

How many miles on it, and when was the last time you put fresh brake fluid through the system (knowing that it is a self-bleeding system, so not sure how well that does getting the nasty stuff out of the slave).

Who did the install? I'm assuming a slave shim was required, but did anyone make note of the clearances?

Unfortunately, this is likely going to be something that may require pulling the transmission to see what's going on in there.

Luckily for you, Nth Moto is a stand-up company...have you reached out to Aaron to get his thoughts? That would be at the top of my to-do list for sure.

[SRT_BluByU]

I seem to recall reading something about one of these aftermarket clutches needing a shim on the slave cyl.. sorry i cant remeber more details if it was this clutchor not.. maybe a lead for you.. hopefully not a wild goose chase.

[Steve M]

I seem to recall reading something about one of these aftermarket clutches needing a shim on the slave cyl.. sorry i cant remeber more details if it was this clutchor not.. maybe a lead for you.. hopefully not a wild goose chase.

The Nth Moto clutch does indeed require a slave cylinder shim, at least for Gen 4 applications. Pretty sure the Gen 5 is the same.

Procedure for measuring is described in detail here: https://driveviper.com/forums/thread...l=1#post373671

[Jack B]

Steve

It is the same for the G5. A shim is an understatement, it is fairly complex machined part, the back side is a press fit on to the boss on the trans.

The unfortunate part of this is, a new slave will probably fix the problem, however, the clutch should also be inspected by NthMoto. As yolu said, the clearance should be carefuly documented.

DSC01833.jpg

The Nth Moto clutch does indeed require a slave cylinder shim, at least for Gen 4 applications. Pretty sure the Gen 5 is the same.

Procedure for measuring is described in detail here: https://driveviper.com/forums/thread...l=1#post373671

[Steve M]

Steve

It is the same for the G5. A shim is an understatement, it is fairly complex machined part, the back side is a press fit on to the boss on the trans.

The unfortunate part of this is, a new slave will probably fix the problem, however, the clutch should also be inspected by NthMoto. As yolu said, the clearance should be carefuly documented.

DSC01833.jpg

Interesting...shim in mine looked nothing like what you show.

Mine looked like the top shim in this pic:

https://driveviper.com/forums/thread...l=1#post347210

Just a piece of plate steel with a couple holes.

[13COBRA]

Do you smell the clutch? Did it slip during One Lap?

[ViperGeorge]

No clutch smell. Maybe 5,000 miles on it. Clutch does not seem to slip. Mark Jorgensen did the install at Woodhouse. Brake fluid was change recently. I don’t know about shims I will ask Mark.

[13COBRA]

No clutch smell. Maybe 5,000 miles on it. Clutch does not seem to slip. Mark Jorgensen did the install at Woodhouse. Brake fluid was change recently. I don’t know about shims I will ask Mark.

That's really interesting. Makes me think it might not be the clutch itself and more of a sensor or something? If it was slipping you'd definitely smell it...and with the miles you've put on it in the last week, you'd notice it slipping.

Do the Gen Vs have a clutch sensor that could be going bad? Do you have to press the clutch all the way to the floor and then some to start the car?

[SRT_BluByU]

Geroge - Out of curiosity why did ya change out the factory clutch? Curious how many miles ya got out of it.. Ive had good luck with the factory unit but am totally bone stock.

[Steve M]

My experience (so far) with the Nth Moto clutch is that it doesn't really slip, even when you try to. I've never smelled anything from this clutch actually, and I've beat on it pretty good over the many years it's been installed in my car.

Next question: does it only do it when the car is hot, or do it also do it from a cold start?

Cooked clutch fluid can wreak havoc on the hydraulics.

[13COBRA]

My experience (so far) with the Nth Moto clutch is that it doesn't really slip, even when you try to. I've never smelled anything from this clutch actually, and I've beat on it pretty good over the many years it's been installed in my car.

Next question: does it only do it when the car is hot, or do it also do it from a cold start?

Cooked clutch fluid can wreak havoc on the hydraulics.

Great point.

First thing I'd do is replace all of the brake fluid.

[ViperGeorge]

Brake fluid (Motul 600) was changed before One Lap but I suspect the fluid in the slave could be dirty since it shares the brake fluid and there is no separate clutch bleed screw.

I will have to check cold starts. I know it does it when hot.

[Steve M]

Brake fluid (Motul 600) was changed before One Lap but I suspect the fluid in the slave could be dirty since it shares the brake fluid and there is no separate clutch bleed screw.

I will have to check cold starts. I know it does it when hot.

It doesn't take much to cook the fluid, especially if you are running hard for any period of time. And your 9L generates even more heat, so there's that. It just doesn't seem like you can ever insulate the lines well enough to keep the heat in check since they run so close to the engine/exhaust.

I wish you luck in tracking down the source of the problem...it's not fun, but hopefully you can get it figured out and move on to more important things in life.

[ViperGeorge]

Does anyone know how to bleed/flush the clutch?

[ViperGeorge]

Geroge - Out of curiosity why did ya change out the factory clutch? Curious how many miles ya got out of it.. Ive had good luck with the factory unit but am totally bone stock.

I changed to the Nth Moto clutch because I upgraded the engine to 9 liters with 800HP and 790 torque.

[SRT_BluByU]

I changed to the Nth Moto clutch because I upgraded the engine to 9 liters with 800HP and 790 torque.

yes.. that sounds like a logical direction. ha! Thanks George!

[13COBRA]

In the Gen Vs, I'm almost positive it all runs through the brakes...so unless Nth Moto has a remote bleeder set up, I'd flush about 3 bottles through the brakes.

[Steve-Indy]

Nick is correct...the stock Gen V has no clutch bleeder. It shares the brake reservoir with the brakes. Supposedly the design of the plumbing automatically rids the clutch hydraulic line of any air.

As you might guess, one can disconnect the line to bleed the system.

George, do you need a few screen shots of this procedure as outlined on the 2014 CD for the the stock system?

[ViperGeorge]

Nick is correct...the stock Gen V has no clutch bleeder. It shares the brake reservoir with the brakes. Supposedly the design of the plumbing automatically rids the clutch hydraulic line of any air.

As you might guess, one can disconnect the line to bleed the system.

George, do you need a few screen shots of this procedure as outlined on the 2014 CD for the the stock system?

Steve, if you have a procedure for bleeding a Gen 5 clutch I would love to have a copy. gbatejan@gmail.com

[TKO MOTORSPORTS TEAM]

Steve, if you have a procedure for bleeding a Gen 5 clutch I would love to have a copy. gbatejan@gmail.com

Here is the " hot bleed" procedure we use on just about every thing from LMP cars to street cars in the pits or shop; gets you the best results quickly because it cycles all old fluid out and removes air on some difficult to bleed calipers and on the 5th gen viper gets the clutch fluid kinda partially changed. Its does require a friend and some coordination.

1. start at any wheel doesnt really matter. Dual bleeders doesn't matter what one you start with either. If your doing it in the hot pits ( not that you should but sh-t happens) do front corner closest to wall first; last should be rear corner closest to pit wall.
2. You will need a bleeder bottle 20oz or so with hose that fits bleeder nipples tightly. Use bleeder bottle with hook or loop to hold bottle on wheel studs or spindle while your bleeding. Plastic bleeder bottles with magnets to hold them not so great on hot as surface of the sun brake rotors
3. Have someone sit in car ready to pump brakes while your on the caliper bleeder
4. Open bleeder and have the person in driver seat pump brakes 4 times with the caliper bleeder open. Have them call out the pumps "1", "2", "3". On the forth pump have them push slowly down while you close the bleeder and you say " closed". Make sure you get the bleeder closed before the brake pedal hits bottom. Its takes a little time to get the coordination between person pumping the brakes and the person bleeding the brakes.
5. Check brake fluid reservoir fluid level and fill it. You will be changing all the fluid in the lines and calipers so make sure the reservoir or reservoirs are full when bleeding
6. On the 5th gen viper hold the clutch pedal down for a few seconds and pump a couple of times after your done bleeding the second corner brake caliper. This will get a little fresh fluid into the clutch slave.
7. Check brake fluid reservoir fluid level before you bleed last corner. Best bet is to over fill the brake fluid reservoir and then bleed the last corner. If you estimate correctly the brake fluid reservoir will be at correct level when your done bleeding last corner.

[ViperGeorge]

Here is the " hot bleed" procedure we use on just about every thing from LMP cars to street cars in the pits or shop; gets you the best results quickly because it cycles all old fluid out and removes air on some difficult to bleed calipers and on the 5th gen viper gets the clutch fluid kinda partially changed. Its does require a friend and some coordination.

1. start at any wheel doesnt really matter. Dual bleeders doesn't matter what one you start with either. If your doing it in the hot pits ( not that you should but sh-t happens) do front corner closest to wall first; last should be rear corner closest to pit wall.
2. You will need a bleeder bottle 20oz or so with hose that fits bleeder nipples tightly. Use bleeder bottle with hook or loop to hold bottle on wheel studs or spindle while your bleeding. Plastic bleeder bottles with magnets to hold them not so great on hot as surface of the sun brake rotors
3. Have someone sit in car ready to pump brakes while your on the caliper bleeder
4. Open bleeder and have the person in driver seat pump brakes 4 times with the caliper bleeder open. Have them call out the pumps "1", "2", "3". On the forth pump have them push slowly down while you close the bleeder and you say " closed". Make sure you get the bleeder closed before the brake pedal hits bottom. Its takes a little time to get the coordination between person pumping the brakes and the person bleeding the brakes.
5. Check brake fluid reservoir fluid level and fill it. You will be changing all the fluid in the lines and calipers so make sure the reservoir or reservoirs are full when bleeding
6. On the 5th gen viper hold the clutch pedal down for a few seconds and pump a couple of times after your done bleeding the second corner brake caliper. This will get a little fresh fluid into the clutch slave.
7. Check brake fluid reservoir fluid level before you bleed last corner. Best bet is to over fill the brake fluid reservoir and then bleed the last corner. If you estimate correctly the brake fluid reservoir will be at correct level when your done bleeding last corner.

Thanks, not sure I follow step 6 though. When you say after doing the second corner brake caliper do you mean after doing all four calipers or just the left two? I usually start passenger side rear caliper (inside bleeder then outside bleeder), then driver's side rear, then passenger side front, and last driver's side front. I've always been under the impression that you bleed the calipers furthest from the master and work your way closer. By the way I use a Motive pump bleeder so no need to have my wife pump, pump, pump, hold. She hated helping me bleed the brakes.

- - - Updated - - -

How long does it take someone that knows what they are doing to change the slave cylinder?

[13COBRA]

Thanks, not sure I follow step 6 though. When you say after doing the second corner brake caliper do you mean after doing all four calipers or just the left two? I usually start passenger side rear caliper (inside bleeder then outside bleeder), then driver's side rear, then passenger side front, and last driver's side front. I've always been under the impression that you bleed the calipers furthest from the master and work your way closer. By the way I use a Motive pump bleeder so no need to have my wife pump, pump, pump, hold. She hated helping me bleed the brakes.

- - - Updated - - -

How long does it take someone that knows what they are doing to change the slave cylinder?

When I did my Gen IV ACR and the VCC, it was 2-3 hours.

[TKO MOTORSPORTS TEAM]

Thanks, not sure I follow step 6 though. When you say after doing the second corner brake caliper do you mean after doing all four calipers or just the left two? I usually start passenger side rear caliper (inside bleeder then outside bleeder), then driver's side rear, then passenger side front, and last driver's side front. I've always been under the impression that you bleed the calipers furthest from the master and work your way closer. By the way I use a Motive pump bleeder so no need to have my wife pump, pump, pump, hold. She hated helping me bleed the brakes.

- - - Updated - - -

How long does it take someone that knows what they are doing to change the slave cylinder?

Second corner just means after you have bleed two calipers. When you hot bleed you dont have to start at farthest corner away from master cylinder. Sequence of bleeding the brakes is just efficiency ( fastest way)and safety. You want to start at the front and end in the back. That way your not in the way or get run over when the car leaves. You dont have to do it this way its just the way we do it so we have the same process every time. We dont use any type of pump or pressure bleeders. For a few reasons. 1. wastes brake fluid. 2.pressure bleeders are slow 3. Once the brake fluid is out of a hermetically sealed container it starts to pick up atmosphere. Any amount of atmosphere ( water) in the fluid lowers its boiling point, lower boiling point= air in fluid...air in fluid=BAD

Clutch slave change 4-5 hours roughly. If you have done it a few times. If you have never done it give yourself a day or two dont rush it

[ViperGeorge]

I confirmed with Mark Jorgenson that they did use a slave cylinder shim per Nth Moto instructions. Mark says that Nth Moto gives very detailed instructions on install which they follow. He says they have installed several and to him they all seem to grab high up on pedal release. Mine grabs high too. In fact 3R Racing in Denver commented on this when they did a check out on the car. 3R used to race Vipers.

Jack, why will a new slave cylinder fix this issue?