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8/13/2018 5:35 PM  #1


65 Mustang jumps when trying to engage clutch

I have a 1965, 289 V-8, 4-speed Borg/Warner T-10, 3.55 gears.

The car started life as an automatic. I bought all of the original parts from a 65 GT to make the conversation to the manual. I changed the ring and pinion to the 3.55. The car jumps when engaging the clutch in 1st gear. I know the clutch in the car is a 10 inch. I was recently told that the 65 GT's have a 10.5 inch clutch instead of the 10 inch installed. Would changing to the 10.5 or 11 inch remedy the problem described? If not, where do I look for a solution? The violent action it makes has already compromised the pinion seal. Thanks in advance for any assistance.

Mike

 

8/13/2018 6:24 PM  #2


Re: 65 Mustang jumps when trying to engage clutch

Welcome BTW................great bunch of guyz with lotsa knowledge .
Jumps huh?!
Mines  a 10 incher and works great. Don't think that is your problem.
Need more info....Did you use the infamous Z-bar (factory set-up) or did you go to a cable set-up?
Just a WAG butt......sounds like its either out-of-adjustment or.....linkage or mounts(motor or tranny) are loose.
What kind of clutch/pressure plate?? Stock or racing style?
Need more info
6sally6


Get busy Liv'in or get busy Die'n....Host of the 2020 Bash at the Beach/The only Bash that got cancelled  )8
 

8/13/2018 8:05 PM  #3


Re: 65 Mustang jumps when trying to engage clutch

Not sure how else to describe it. I have watched it drive away under those conditions and there is a lot of movement underneath the car that shouldn't be. One might describe it like wheel hop. It moved enough to ruin the pinion seal. I used the factory z-bar, The pressure plate is stock. The pressure plate, throw out bearing and disc were new on install. The stock shifter was replaced with a Hurst Competition Plus. The shift rods had to be cut down and rebuilt because Hurst does not make levers for the B/W T-10. I bought the clutch parts and the ring and pinion from Speedway. Thanks.

Mike

 

     Thread Starter
 

8/13/2018 8:22 PM  #4


Re: 65 Mustang jumps when trying to engage clutch

Sooo when you ease the clutch out does it kinda chatter?
If so...it could be oil contaminated clutch (from engine's rear main seal.
(just sorta  think'in put loud here)


Get busy Liv'in or get busy Die'n....Host of the 2020 Bash at the Beach/The only Bash that got cancelled  )8
 

8/13/2018 9:50 PM  #5


Re: 65 Mustang jumps when trying to engage clutch

Welcome to the site Mike. Have you agree with Sal about the adjustment if it's jumping when you go into first gear. Seem like there would be some gear grinding too.

What's moving under the car that shouldn't be?

How are the pinion bearings? It's the only thing I can think of that can cause the pinion seal to go bad. It will also cause the U joints to fail way too soon. Have you tried to move the driveshaft at the U joints to see how much movement is there?


John  -- 67 Mustang Coupe 390 5 speed
 

8/14/2018 6:39 AM  #6


Re: 65 Mustang jumps when trying to engage clutch

Hello , i bet 50 bucks on flywheel that was not re-surfaced before placing the new clutch.
Maybe some grease or oil could have contaminated the clutch.
This is the same problem as mine.
The jump you feel are the spring inside the clutch that are working .
It's a mix between slip and engaged , so that jump.
If temperature rise you will feel more jump .
To have less jump as possible ( until you have surfaced )  is not to play so much with clutch lever. 
Let it engage as quick as possible at low revs and starts move, then the others will go easy.
thats my two cents

 

8/14/2018 7:38 AM  #7


Re: 65 Mustang jumps when trying to engage clutch

Mine had a chatter and violent shake when I first let the clutch out and it was fine while driving.  My issue was the Mr Gasket Pressure plate bolts were slightly to long.  So my pressure plate was not completely against the flywheel even though the bolts were torqued to specs.   My guess is its something with the clutch or pressure plate.

 

8/14/2018 8:15 AM  #8


Re: 65 Mustang jumps when trying to engage clutch

I don't recall hearing any chatter. The only time it grinding is sometimes going into reverse. The car does not jump going into 1st gear, it does it when the clutch is let out. Releasing the clutch faster only exaggerates the problem. Tried various rpm's while engaging slower and faster. The rear seal on the motor has a small leak. Oil contamination is possible. The flywheel was resurfaced and the ring gear was replaced when the swap from auto to manual was made. The rear end was opened up when the gears were changed and I was told everything looked good. U-joints are new. It looked like there is up and down movement of the driveshaft/rear end. You can use 2nd gear from a stop and it does not "jump". The transmission was rebuilt by our local transmission shop before it was installed. The transmission mounts were replaced using new mounts from CJ Pony.

     Thread Starter
 

8/14/2018 9:10 AM  #9


Re: 65 Mustang jumps when trying to engage clutch

When my '67 coupe had this problem it turned out to be a broken motor mount.

 

8/14/2018 11:43 AM  #10


Re: 65 Mustang jumps when trying to engage clutch

Mike Fox wrote:

I don't recall hearing any chatter. The only time it grinding is sometimes going into reverse. The car does not jump going into 1st gear, it does it when the clutch is let out. Releasing the clutch faster only exaggerates the problem. Tried various rpm's while engaging slower and faster. The rear seal on the motor has a small leak. Oil contamination is possible. The flywheel was resurfaced and the ring gear was replaced when the swap from auto to manual was made. The rear end was opened up when the gears were changed and I was told everything looked good. U-joints are new. It looked like there is up and down movement of the driveshaft/rear end. You can use 2nd gear from a stop and it does not "jump". The transmission was rebuilt by our local transmission shop before it was installed. The transmission mounts were replaced using new mounts from CJ Pony.

Ok ... keep me updated , i am interested in this solution when all will runs fine . thanks !

 

8/14/2018 4:25 PM  #11


Re: 65 Mustang jumps when trying to engage clutch

Michael H. wrote:

When my '67 coupe had this problem it turned out to be a broken motor mount.

                                    ^^^^Maybe!^^^^^.........Do you "feel" any weird movement/rocking in your accelerator foot when you  let out the clutch and give it a little gas? 


Get busy Liv'in or get busy Die'n....Host of the 2020 Bash at the Beach/The only Bash that got cancelled  )8
 

8/14/2018 5:36 PM  #12


Re: 65 Mustang jumps when trying to engage clutch

Have another work the clutch while you watch the Z bar.   It should pivot nicely on either end and not
have any fore / aft play.   I found even with a new Z bar and those crummy little plastic bushes (new),
I still had play in the Z bar.   I cut up some brass sheet stock and lined the holes in the Z bar to basically
close up the hole slightly and that helped my shudder problem.

 

8/15/2018 6:35 AM  #13


Re: 65 Mustang jumps when trying to engage clutch

The problem with the steering, suspension, brakesand clutch linkage on these Mustangs is people sample them when they are flat worn out and think that’s how they drove new. The truth with fresh new parts and a little attention to detail these systems work quite well. On my 66 I swapped out my C4 for a Toploader 4 speed. In 8 years I’ve had zero issues even when I had a broken motor mount.

What concerns me is the use of used parts. I think your problems with grinding are the flywheel which I feel in your case no amount of resurfacing is going to fix and wear on the related linkage and Z bar that are stacking up. I’ll bet it will only make it worse. Flywheels have a finite service limit. They can only or should only be cut a couple times before being scrapped. Every time you cut the flywheel and make it thinner, you move the clutch assembly away from the clutch fork and throw out bearing. The clutch fork only has so much travel before it can no longer fully disengage the clutch and the clutch drags making it harder to shift or grind going into gear. I’ll bet that is the issue. Your flywheel is 50+ years old, how many times in that time has it been cut and how many?

When I converted my car I did reuse a flywheel but it was with in spec. I bought a brand new Z bar and Z bar bracket and ball studs. I made my own clutch linkage with rod ends. I installed Steve’s hanger bearing kit which IMO is a must do and worth every penny, thank you Steve!
Making the fancy clutch linkage was stupid easy and cheap. A tape measure, marker, hacksaw, file and a 3/8x24 die were all the “special” tools needed and about a half hours time. My Z bar system works easy and silky smooth and 100% trouble free in 8 years.

2 years ago when I put my GT40P in that everyone says you need special expensive headers, I used readily available reasonably priced off the shelf longtubes that not only work with the plug angle but clear the clutch linkage just fine and don’t need a drop bracket for the PS ram. When I put that motor in I bought a new flywheel. IMO flywheels and harmonic balancers should be considered consumable items and be replaced. I bought a PRW SFI rated billet flywheel. It uses a bolt on weight as well as being drilled for every possible SBF clutch kit including metric 5.0 with dowels. It was about $225 to my door. Besides being new, my feet are worth that bit of safety to my.

Here is my clutch linkage

Last edited by Huskinhano (8/15/2018 6:39 AM)


I'm not a complete idiot.....pieces are missing. Tom
 

8/15/2018 2:06 PM  #14


Re: 65 Mustang jumps when trying to engage clutch

Huskinhano wrote:

2 years ago when I put my GT40P in that everyone says you need special expensive headers, I used readily available reasonably priced off the shelf longtubes that not only work with the plug angle but clear the clutch linkage just fine and don’t need a drop bracket for the PS ram.

Just out of curiosity, what headers did you run with the P heads?

 

8/15/2018 2:41 PM  #15


Re: 65 Mustang jumps when trying to engage clutch

Michael H. wrote:

Huskinhano wrote:

2 years ago when I put my GT40P in that everyone says you need special expensive headers, I used readily available reasonably priced off the shelf longtubes that not only work with the plug angle but clear the clutch linkage just fine and don’t need a drop bracket for the PS ram.

Just out of curiosity, what headers did you run with the P heads?

Off the shelf MAC longtubes. I used Streetfire wires by MSD because the boots are nice and compact and I used DSE boot protectors. While not designed to work with the P head they fit well enough. I did not have to ding any tubes for clearance but I had to ding a couple tubes for frame rail clearance, just barely cleared in stock form but it could have been just my car. Also for the Z bar shaft slightly but absolutely no issues at all with the rest of the clutch linkage. The driver's side was actually pretty easy to get in. #5 tube slips in after the main part is in. No issues with anything 2 years later, no burned wires or leaking gaskets.

Everyone disses these motors but I love mine. They are cheap, last a long time and run really, really well with a 5.0 cam! I was talking with someone on FB who has a Fox body with GT40P heads, basically the exact same combo as mine. He said with 3.27 gears and a T5 he was running low 13's. I just picked one up for a buddy who lunched his 289 in his 66 during a autocross even. I picked up a nice clean 118K motor complete for $80, $50 core charge and $100 to pull it. I could have pulled it for free but that $100 was well worth it!


[img][/img]
 

Last edited by Huskinhano (8/15/2018 2:46 PM)


I'm not a complete idiot.....pieces are missing. Tom
 

8/15/2018 3:01 PM  #16


Re: 65 Mustang jumps when trying to engage clutch

Nice!  Thank you for sharing.  Is there enough clearance to change the spark plugs with the headers in place?

 

8/15/2018 4:26 PM  #17


Re: 65 Mustang jumps when trying to engage clutch

No, you’re going to have to unbolt the header to get to the last two plugs. But things like this are to be expected with any header swap. Plus just about every one runs electronic ignition and platinum plugs so you should be able to go a very long time before plug changes. I have platinum plugs but a points distributor temporarily. I’m going electronic. I have a Crane CD box I got cheap I just have to figure out where I want to put it. I’m thinking of moving the battery to the trunk so the CD box will go where the battery was. Kind of the knee bone connected to the thigh bone thing. Oh plus time.


I'm not a complete idiot.....pieces are missing. Tom
 

8/16/2018 8:56 AM  #18


Re: 65 Mustang jumps when trying to engage clutch

Michael H. wrote:

When my '67 coupe had this problem it turned out to be a broken motor mount.

 
That would be my guess too. I had that same problem same symptoms on my 52 Hudson a while, a loooong while, back. It was the motor mount. If it is it's usually pretty obvious, a lot of execcive movement by the motor itself.


"anyone that stops learning is old, whether at twenty or eighty"Henry Ford
 

8/16/2018 12:59 PM  #19


Re: 65 Mustang jumps when trying to engage clutch

Mike Fox wrote:

I have watched it drive away under those conditions and there is a lot of movement underneath the car that shouldn't be. One might describe it like wheel hop. It moved enough to ruin the pinion seal. 

Please tell us exactly where you see movement!  Is the rear of the driveshaft and pinion yoke moving up and/or down while the rear end stays stationary?

Mike, this forum is full of sincere people with great experience, and great problem solving skills. (many of us are old guys).  Please keep in mind we don't know you, your skill set,  or your car, but would find no greater satisfaction than to help you diagnose and fix a problem.  A lot of us have/had  65 Mustangs, and I am fairly certain, that whatever your car's issue is, someone here has had that same problem, and fixed it.  I would recommend looking at one topic at a time.  Examine the clutch linkage to confirm or deny the problem.  Then look at the motor mounts.  If that's not the problem, look at the trans cross member and trans mount.  If that's not the issue, examine the rear end items.  Ask specific questions along the way.  BE SAFE when you crawl under that thing!

 

8/16/2018 5:28 PM  #20


Re: 65 Mustang jumps when trying to engage clutch

TimC wrote:

   
  Please keep in mind we don't know you, your skill set,  or your car, but would find no greater satisfaction than to help you diagnose and fix a problem.  A lot of us have/had  65 Mustangs, and I am fairly certain, that whatever your car's issue is, someone here has had that same problem, and fixed it.  I would recommend looking at one topic at a time.  Examine the clutch linkage to confirm or deny the problem.  Then look at the motor mounts.  If that's not the problem, look at the trans cross member and trans mount.  If that's not the issue, examine the rear end items.  Ask specific questions along the way.  BE SAFE when you crawl under that thing!

Very well said Tim


John  -- 67 Mustang Coupe 390 5 speed
 

8/17/2018 7:23 AM  #21


Re: 65 Mustang jumps when trying to engage clutch

I just got the car back from the shop yesterday, had to replace the speedometer. I will be able to make an inspection on Monday. I really appreciate the help figuring this out. My wife and I have had 2 other 65's and a 95 mustang. We had the other 65's 40 years ago and this car was a birthday present for her a couple of years ago. I agree with the insight regarding the flywheel. I did take it to a NAPA auto shop and they resurfaced it. The motor and or transmission mounts will be the focus when I can get back over to it. I will keep you all informed of the findings and cause.
Thanks to all!

Mike 

     Thread Starter
 

8/17/2018 12:17 PM  #22


Re: 65 Mustang jumps when trying to engage clutch

Check condition of the pilot shaft bearing in the rear of the crankshaft.  Also, be sure the throwout bearing can easily slide on the tranny bearing retainer tube.

All 65 V8's used 10" clutch.


Money you enjoy wasting is NOT wasted money... unless your wife finds out.
 

8/26/2018 2:24 PM  #23


Re: 65 Mustang jumps when trying to engage clutch

Thanks to all for the input. It has helped. I checked the motor mounts and transmission mounts and they all look good. I have taken the car to our local transmission shop and had the shop foreman ride with me. He believes that it is either the flywheel or the clutch disc that is grabbing, may be oil contamination or some other substance. He is a very competent mechanic, they are booked up until the end of next month. So it will be a while before they can make the repairs. I'm smart enough to know when I'm out of my area of expertise. That's one reason why I approached this forum, and a professional. I will relay the results when it is completed. Again, thanks to everyone.
Mike
 

     Thread Starter
 

8/26/2018 3:58 PM  #24


Re: 65 Mustang jumps when trying to engage clutch

Sorry that I'm late to this game, but two things I suggest to check ...
1.  Verify first gear is fully engaged; engine off, put the shifter in first gear, get under the car, remove the shifter rod and see if you can move the lever further to fully engage the first gear slider.
2.  Verify your driveshaft is not too long, the slip yoke in the transmission should have about 1" of play with the car on the ground.  This may be how the pinion seal was ruined.


65 Fastback, 351W, 5-speed, 4 wheel discs, 9" rear,  R&C Front End.
 

8/27/2018 7:30 AM  #25


Re: 65 Mustang jumps when trying to engage clutch

BobE wrote:

1.  Verify first gear is fully engaged; engine off, put the shifter in first gear, get under the car, remove the shifter rod and see if you can move the lever further to fully engage the first gear slider.

Before trying this be sure your parking brake is set and wheels are chocked.  One time I was doing something similar and didn't have the brake set or wheels chocked (dummy me) and accidentally knocked it into neutral.  The car began to roll with me underneath it.  I got out of the way, but it was a very close call and could have gone very badly.
 

 

Board footera


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