Clutch Adjusting 101

[CatMan1]

I'm going to see about adjusting the clutch on my '28 Sports Coupe. I'm chasing a gear grinding issue as of late. I think it's more of a cold weather driving technique sort of thing since it started when it got cold (50's) and then I changed the fluid to 600W. Anyway.....what is the proper way to measure the travel? I assume with the end of the tape measure on the floor and gently push the pedal down till I feel resistance then measure from the back of the pedal? How much of a difference does the steering column/pedal seal mat make?



P.S. I've tried all sorts of shifting techniques.....fast shifting, slow shifting, double-clutching. They all might work once or twice, but not again. The super-fast shifting did work best.

[J Franklin]

you will measure the same amount of travel either from the carpet or bare floorboard, or the ground for all good reason.

[nkaminar]

CatMan, You can measure it anyway you want. Franklin has the right response. Should be 1 inch free travel before you feel resistance. The reason is to prevent the clutch pedal from causing the clutch to slip which wears out the clutch in no time.

Drain out the 600W and replace with multi grade 85W-140 G5. This modern transmission oil will reduce the wear in your transmission and will act like a thinner oil in cold weather and a thicker oil in warmer weather.

[jb-ob]

Catman,

You need to tell us what type of clutch you have in your '28 ?

Until the end of October, most '28 clutches were the multi-disc style requiring a pedal free play of 3/4".
A later single disc clutch required 1" free play.

Once you decide what clutch you have and adjust properly, test drive. Not likely you have all NOS adjusting parts so to compensate you could 'shorten' the adjustment slightly.

What ever you do, make only one change at a time & test drive. 90 years later each of these cars has their own personality to deal with.

[1crosscut]

When its cold I start out shifting quickly between gears. As I get more miles in and things start to warm up then my shifting between gears slows down. Many days I can work my way through the warm up process and hit all the gears perfectly. Then there are the days I just can't seem to get it right to save my life. Oh the fun of driving a Model A.

[Cape Codder]

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I sure would like an idea of how many of you use modern 85W-140 G5 oil in the transmission vs the 600W in the Transmission?

[chrs1961815]

That's just the thing: I think most of the 600w you buy from suppliers isn't really like the original 600w but a modern substitute. Whether it makes any sifference is up for debate.

[J Franklin]

Originally Posted by Cape Codder

I sure would like an idea of how many of you use modern 85W-140 G5 oil in the transmission vs the 600W in the Transmission?

I use 140 GL4

[nkaminar]

Mitchell, who make a very nice modification of the standard transmission with synchronized second and third gears and a nice overdrive, recommend the 85W-140 G5 oil in their products.

[jb-ob]

I'm no 'Mitchel', but it has been claimed that GL5 gear oil can be unsafe for 'yellow metals' ie. Model A reverse idler gear bushings.

Valvoline still makes a GL4 85-140 gear oil or using straight 140 W might be safer choice.

'Your mileage will vary'.

[Patrick L.]

Clutch adjustment. As mentioned the starting point for the free-play doesn't make much difference. Make sure the clutch pedal comes back to the top fully on its own. Then adjust the linkage so the free-play in the pedal from fully released position [top] to just starting to feel resistance is 1.0-1.5". Removing and looking thru the bell housing inspection cover helps. The clutch release bearing should not contact the pressure plate fingers when the pedal is released top/up position.

Gear oil. 600W can be anywhere from about 150-240 weight. I don't see much difference between 140 or 250. 140 works just fine.

[CatMan1]

I checked the clutch travel and it looks like it should be. It was cold in the garage when I started out Sunday afternoon and in the upper 60's out. I started out shifting QUICK and it worked fine. As I drove on I shifted it via 'double-clutching' and it worked fine; both up-shifts. Shifted beautifully. Now, this does bring to mind a question......The Owner's Manual never talks about 'double-clutching' to up-shift, but yet many here do and it does work. Wonder what Henry never recommended it? Does anyone else notice that the 1-2 shift is done differently than the 2-3? Is it just me?

[Patrick L.]

Its not a problem to double clutch the upshifts, its just not needed.

If the clutch is working as it should, good.