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BJ8 clutch activation problem

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HBJ83341 Avatar
HBJ83341 Warren Voth
El Cajon, CA, USA   USA
This is a re-posting of my clutch problem of about 6 weeks ago

I have had an unfathomable clutch problem with my ‘66 BJ8 Austin Healey for over six months. It’s become increasingly dangerous to the point the car is becoming no longer safe to drive. It began with the replacement of the clutch master and slave cylinders and slave cylinder flex line. It is important to note this problem didn’t exist prior to these recent replacements. And I have owned the car since 1967 and have never had this problem before. The overall mechanical condition of my car is first rate. and it gets first rate maintenance.

On the road, I feel the clutch depression become increasingly heavy while shifting, until the petal will no longer depress. As I continue with more force, with my foot, to work the clutch petal to shift, suddenly I feel what ever is restricting the petal give way as if overcoming the resistance. I then hear and “feel” a “clunk “ in the petal, with my foot, as the clutch petal returns to normal. The feeling, and sound comes from the direction of the clutch and brake petal box bracket.

My first thought was the replacement Lucas master cylinder was defective. A second replacement cylinder was installed. The problem remained.

Next, the replacement slave cylinder flex line was replaced with a new line. The problem remained.

That slave cylinder flex line was replaced with a braided stainless steel flex line. The problem continued.

I have talked with the Toy Shop- Terry Cowan, of San Diego, CA, Randall Zoller of Heritage Motorsports of El Cajon, CA, Eric Gurnden of Absolutely British in Santa Maria, CA.

I have been on the Online, on this site, for suggestions before. While I received many ideas, none of them helped.

I have posted my problem on the AHCA website. Again, I have received suggestions of things I have already checked.

I have checked the clutch and brake petal shaft and bushings in the petal bracket. No problems there. Everything is free.

I have been under neath the car to check the slave cylinder. No problems and everything is clear. And it works as expected.

My next thought is the problem is inside the bell housing and clutch itself. Perhaps the throw-out bearing is worn or the clutch fork to the throw-out bearing is binding? The “clunk” sound doesn’t come from that direction. And I have never heard of anything in the bell housing working intermittently.

But, I have been able to go for long periods of driving time with the clutch function as normal. Then, when least expected, the problem returns. This leads me to think the problem is not in the bell housing

I have been unable to find any INTERNET information of intermittent clutch problems with the diaphragm clutch that BJ8's have. The answers I have gratefully received tell me that this problem could be unique to my car.

I will be replacing the slave cylinder, again, although I don't think this will be the solution. But I must cross it off the list...

Any ideas new ideas... anyone...anywhere...

Warren Voth
vothstir@aol.com

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RTaillieu Avatar
RTaillieu Rick Taillieu
Leamington, ON, Canada   CAN
Have you checked up in the pedal box for something jamming the clutch pedal? Are the return springs on the clutch and brake pedals attached?



Rick
'64 BJ8 P1

HBJ83341 Avatar
HBJ83341 Warren Voth
El Cajon, CA, USA   USA
Thanks for your reply, Rick,

I have checked that as well as two other Healey mechanics and others. Everything seems fine in the petal box and the petals swing free. Your suggestion was one of my first thoughts. The petal box seems perfect. However, I am going to disconnect the clutch and brake master cylinders again and try to rotate, and rock the petal to rotate the inner bushings as well as the spacer, on the shaft, between the petals. I am hoping for a miracle...

If a miracle happens, I will; post it on this site...

Again, thanks for your reply

Warren Voth

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RTaillieu Avatar
RTaillieu Rick Taillieu
Leamington, ON, Canada   CAN
Does it only happen when you're driving or can you duplicate it when parked?



Rick
'64 BJ8 P1

HBJ83341 Avatar
HBJ83341 Warren Voth
El Cajon, CA, USA   USA
Hi Rick,

Thanks for staying with me on this... The other day, when I stopped for a red light, the clutch petal problem began again... I pushed the shift into neutral, and turned off the ignition. Then, I turned on the ignition. The petal was still heavy. I feel the problem could be the release bearing fork or the slave cylinder push rod, which I have not checked. I am planning on replacing the slave cylinder, again. This time, I am going to check the slave cylinder push rod, (which does not come with a replacement slave cylinder). The push rod is fifty years old, could be worn and needs replacement. I am also going to check the release bearing fork for wear. The fork itself or the fork bushings could be worn and need to be replaced, Any of this could be the problem... I hope...

I'll keep you posted... thanks again...

Warren

RTaillieu Avatar
RTaillieu Rick Taillieu
Leamington, ON, Canada   CAN
Warren,

This is definitely a strange one.
When you pull the push rod and the fork check to make sure they aren't bent, it was a common problem with the early Sprites but I'm not sure about the 3000's.
Good Luck



Rick
'64 BJ8 P1

HBJ83341 Avatar
HBJ83341 Warren Voth
El Cajon, CA, USA   USA
That's for sure, Rick,

I do...make that hope...to find something wrong, that's easy to fix. I have been putting a lot of force on something. I hope I haven't broken anything too expensive. The car goes on a lift Monday...

Looks like I can get at everything form the outside.

My '66 BJ8 had the same BRG and and interior as yours. It had about 4000 miles on the OD when we bought it in 67.

Again, thanks for your help. I'll post the problem as soon as I know.

Regards,
Warren

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RTaillieu Avatar
RTaillieu Rick Taillieu
Leamington, ON, Canada   CAN
Warren,

Have you had the gearbox cover off to do any of the previous work?
If not, it might be worthwhile to take it off so you can have a good look at everything from the top as well as the bottom.
It would also be a good time to check the gearbox oil and lube the front U-joint.
It's not really that hard, I just had mine off to change the speedo cable.



Rick
'64 BJ8 P1

RAC68 Avatar
RAC68 Raymond Carbone
NJ, Jersey Shore, USA   USA
Hi Warren,

Just coming back to the Forum and read of your trials and tribulations identifying the cause of your resisting clutch peddle. As described, it sounds as though something is loose and shifting position causing a misalignment when activated and my guess would be the fork pivot has lost its anchoring screw and is moving off center. As you have described, I would first have checked to see if the slave rod is straight and positioned properly to the end of the fork. However, I would guess that an issue here would have been noticeable during your first replacement of the slave cylinder. An occasional misaligning fork pivot would not have been so obvious and, when misaligned, I expect would place additional resistance on the slave and peddle. I also feel that the bang you hear is caused when it regains its proper positioning and the added resistance is released.

This is conjecture on my part and I wish you the best on your identifying the cause,

Ray(64BJ8P1)



Edited 1 time(s). Last edit at 2018-05-14 04:47 AM by RAC68.

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HBJ83341 Avatar
HBJ83341 Warren Voth
El Cajon, CA, USA   USA
Thanks for your input Ray,

This clutch thing has been a trial. I have been through the system from the petal end and there is no problem there. I think at least marking of some sort will show on the fork or push rod. I am concerned that I could damage or break the fork, if that is the problem. I think you are describing what is going on very well.

Tomorrow will tell. I will post what everI find. It's amazing that this problem seems so unique that it must be something very simple but unusual.

Again...Thanks for your input...

Warren

HBJ83341 Avatar
HBJ83341 Warren Voth
El Cajon, CA, USA   USA
HI Rick,

Just checked the oil in the tranny. It's up and clean. I will hit the front U joint shortly

Thanks for your thoughts...

Warren

RAC68 Avatar
RAC68 Raymond Carbone
NJ, Jersey Shore, USA   USA
Warren,

Just to note, as with the rubber pop-out to access the transmission dip stick, there is also a similar rubber pop-out on the left side of the transmission cover under the rug to grease the front universal and slide of the drive shaft, Although both are a pain to get to with the console in place, they do give access and eliminate removing the console and cover.

Ray(64BJ8P1)

HBJ83341 Avatar
HBJ83341 Warren Voth
El Cajon, CA, USA   USA
Thanks for the thought, Ray,

Have popped both plugs out, and as a matter of fact, replaced them with new. I had the drive shaft u-joints rebuilt several years ago. Even had the drive shaft spin balanced. Seems the front u-joint takes more abuse. I usually lube the u-joints and slip joint once a year or so. You're right about the drive shaft, It is easily forgotten and out of sight. It was on my car for many years...years ago.

Regards,
Warren

petnatcar Avatar
petnatcar Silver Member Peter Carbone
Watertown, NY, USA   USA
Warren,

Have you been able to lay under the car while someone operates the clutch?

You may see something sliding or slipping one way or the other and causing
something else to bind up and prevent proper engagement.

This is such a simple system that it has to be something simple causing the problem.

Hang in there, you'll figure it out.

And the word is PEDAL not PETAL (like a flower).

Good luck,
Peter

HotRod416 Barry K
Oconomowoc, WI, USA   USA
I'll throw some thoughts out here. I suspect the length of the push rod. The new components are of slightly different dimensions compared to the original. Take a look at the cup that the rod pushes against and see if it appears to be traveling or wandering around and not always centered. I think I'm correct that the rod floats on one end. Yes? You could make a replacement with a 16d nail that is just a bit longer than the original and see if the problem remains. It's a cheap and simple experiment. In general the problem sounds mechanical rather than hydraulic, but you've thought of that already. What a curious problem...

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