Clutch Adjustment/Transmission Oil
 

Yesterday morning my wife and I took a ride in my ’28 roadster. We drove about 25 miles on rural roads with lots of starts and stops as she likes to photograph the deer and other wild animals she sees. I had been noticing that the car was getting harder to shift (double clutching) and it seemed to be getting worse.

When we got home, I checked the clutch adjustment (pedal should move 1 inch before feeling the clutch starting to engage). It measured about 1-1/2 inches so I decided to adjust it, but I checked the transmission oil first. The fluid was low, so I drained it and filled the transmission with Texaco Thurban SAE 250 fluid. The fluid that I drained out was quite thin and drained out quickly. The Texaco fluid is thick, like honey and took some time to get it into the transmission. I chose this because I had it and 250 weight fluid is recommended by Lyle Meek on the MAGFA website.

I took the car for a test drive and the problem was much worse. It was just about impossible to shift/double clutch without grinding the gears.
This morning I adjusted the clutch so that pedal moves 1 inch until starting to engage. This didn’t help at all.

I fear that I have a much more serious problem. All help and suggestions will be appreciated.

Thanks in advance, Robert

Re: Clutch Adjustment/Transmission Oil
 

Look for a cracked arm on the side of the trans (the clutch linkage attaches to this, when depressed it moves the throw-out bearing to the forks on the p/plate dis-engaging the clutch disc).
Paul in CT

Re: Clutch Adjustment/Transmission Oil
 

Also make sure that there is nothing in the way of full pedal travel when pushing in on the clutch pedal. It doesn't take much of an obstruction to keep the pedal from fully releasing the clutch.


That being said, the cracked arm is a very common culprit.

Re: Clutch Adjustment/Transmission Oil
 

I don’t believe that the arm is cracked or that there is an obstruction. I scraped the paint from the arm and while my wife operated the clutch pedal over and over again, I could not see any problems. I wore strong reading glasses while looking. Before scraping the paint, I noticed that there were cracks in the paint at what I thought would be the arm’s stress points. I’m wondering if the arm has been flexing/bending. My wife and I agree that this clutch takes a too much pressure to get it to the floor. This problem has been growing slowly for some months but just now got to this point.

My other Model A is an early (March ’28) OCPU. It has what I assume is an early clutch/transmission conversion. This clutch pedal takes little effort to floorboard. I have owned both vehicles for over 30 years.

Again, any and all help/suggestions are appreciated.

Thanks, Robert

Re: Clutch Adjustment/Transmission Oil
 

Re: Clutch Adjustment/Transmission Oil
 

Have you watched what is going on when the inspection cover is removed ?

Re: Clutch Adjustment/Transmission Oil
 

Patrick, thanks for your thought. I should have done this.

I just removed the inspection cover and bumped the starter in order to see how it behaved at all positions. My wife operated the clutch while I was doing this. Everything looked OK to me but now I feel it may be that the clutch linings are worn. Before continuing I think I’ll try to adjust the clutch a little tighter than specs to see what happens.

This is going to take some time though because we will be out of town for a few days
.
Thanks again, Robert

Re: Clutch Adjustment/Transmission Oil
 

When you get back at it start with finishing you lubbing job ! Lub the TO bearing, put a few drops of oil on the shaft, grease the pedal bushing, oil the linkages

Also check adjust the engine idle speed !

Re: Clutch Adjustment/Transmission Oil
 

Thanks, Big Hammer, I lube the car regularly, once a year and never drive over 500 miles between servicing.

I needed to put the car in my barn before we left. I had drained the Thurban 250 fluid so I refilled it with Valvoline 80W-85W-90 so I could drive it there. To my surprise it shifted (double shifting) and it works better than it did before I adjusted the clutch. I always believed that the heavier oil makes for easier shifting but that’s not so in my case (go figure). I’m 86 years old and still learning.

Thanks again to all of you, Robert

Re: Clutch Adjustment/Transmission Oil
 

Robert,

I might have suggested that over rated 250 gear lube might be the problem, but in 'warm' Texas ??

My '28 with it's multi-disc clutch is not forgiving about missing shift points unlike a single disc clutch which can be 'wound out'. Could be my car but is my experience.

At my favorite Sunday breakfast spot where old guys meet. They leave together as the oldest needs an entire red light cycle walk across two lanes. When he gets to his car he has to stoop over to open the door ,hang on the roof to get a leg in, pulls the rest of his body in tugging on the steering wheel. He has to lean back out to pull the door closed and finally fires it up...and roars down the street winding out three gears ! His 'senior car' is a orange 'whale tail' 911 Porsche !

You two guys are my hero's .

Re: Clutch Adjustment/Transmission Oil
 

Y-Blockhead, Thanks for the picture of your clutch arm. I’m glad that mine was not like that.

Jb, My PU with the clutch conversion shifts smoothly and the clutch pedal takes less pressure to operate than the one in the roadster. Looking through the inspection cover I see a very primitive looking clutch which bears no resemblance to the one in my roadster. The roadster clutch looks like the one in my ’34 Ford.

I’m kind of like that man you describe except that I’m careful not to pull on the steering wheel too hard and I don’t have a sports car.

Thanks, Robert

Re: Clutch Adjustment/Transmission Oil
 

OH, you have the early multi-disk clutch ?

I didn't know that. So, I can't be much help. Sorry.

Re: Clutch Adjustment/Transmission Oil
 

Robert,

The clutch release arm is longer on a '28 multi-disc transmission giving better leverage than later style Model A. That & a bowl of 'Wheaties' in the AM and you'll be pulling thru them gears like a pro !

Keep enjoying the ride !