MTFCA Forum

Hello
I recently brought my 1926 Runabout out of storage to get it started. When I would attempt to engage the starter the car would try to drag forward. So I jacked it up and put stands under the rear axle, reset the air fuel mixture, choke, crank it over twice, turn on the ignition and it fired right up.

However while I had it up in the air, I was doing some checking, I lowered one rear wheel to the ground and then rotated the other rear wheel in my hands.

How much should I be able to turn the other wheel forward and backward with the brake off and one wheel resting on the ground?

QGolden wrote: ↑

Sun May 15, 2022 6:56 am

Hello
I recently brought my 1926 Runabout out of storage to get it started. When I would attempt to engage the starter the car would try to drag forward. So I jacked it up and put stands under the rear axle, reset the air fuel mixture, choke, crank it over twice, turn on the ignition and it fired right up.

However while I had it up in the air, I was doing some checking, I lowered one rear wheel to the ground and then rotated the other rear wheel in my hands.

How much should I be able to turn the other wheel forward and backward with the brake off and one wheel resting on the ground?

I don't know a figure for "how much", but I can tell you there's normally a lot more play than you would guess there should be. It's an accumulation of all the clearances in your, ring & pinion, universal joint and differential.

With all parts in spec in the drive line and measuring at a wheel nut on a demountable, one inch rock is all that you should be getting.

There should be a difference between the transmission brake set and not set.

Kerry wrote: ↑

Sun May 15, 2022 7:57 am

With all parts in spec in the drive line and measuring at a wheel nut on a demountable, one inch rock is all that you should be getting.

Thanks, I am certainly getting more than an inch!

Art M wrote: ↑

Sun May 15, 2022 10:23 am

There should be a difference between the transmission brake set and not set.

Good point. Thanks.

QGolden wrote: ↑

Sun May 15, 2022 6:57 pm

Kerry wrote: ↑

Sun May 15, 2022 7:57 am

With all parts in spec in the drive line and measuring at a wheel nut on a demountable, one inch rock is all that you should be getting.

Thanks, I am certainly getting more than an inch!

Well, how much are you getting?

The slack in the system is contributed to by the play in the axle gears in the differential and the three spider gears, then the crown wheel and pinion mesh, then the play in the universal joint and then within the transmission components. Kerry's 1" would be the absolute best with everything in original spec. I would expect 3-4" in any setup that had been used for any length of time. When you make a stop in a T, often the car will rock at the end of the stop. This can happen because of the brake being on the transmission. The rock is all the slack in the driveline, compounded by the torque on the drivehaft and axles exerted by the braking force. Slack is normal.

Allan from down under.

While the rear wheel is aloft, check the AXIAL float as well. It needs to be minimal.

Jerry VanOoteghem wrote: ↑

Sun May 15, 2022 7:04 pm

QGolden wrote: ↑

Sun May 15, 2022 6:57 pm

Kerry wrote: ↑

Sun May 15, 2022 7:57 am

With all parts in spec in the drive line and measuring at a wheel nut on a demountable, one inch rock is all that you should be getting.

Thanks, I am certainly getting more than an inch!

Well, how much are you getting?

Not sure, I will Jack it back up and check, I did not measure it. I’d say 3 inches, but will check again as soon as I can.

Chris Barker wrote: ↑

Mon May 16, 2022 11:05 am

While the rear wheel is aloft, check the AXIAL float as well. It needs to be minimal.

Thanks, presume you mean lateral play (in and out) I will check again, I only checked one side and it was not discernible.