MTFCA Forum

My 9-17-23 post regarding this subject is getting long, so I will provide an UPDATE here.

As Criag Leach recommend in the original post, I purchased a laser thermometer and have taken a number of readings after a 20 mile run. During the run, I never applied the brake pedal. As shown in the photo, I installed a shield between the end of the muffler and the axle.

Left Disc Rotor -- Left Emergency Brake Drum -- Pumpkin Right Disc Rotor -- Right Brake Drum

Prior to Run ==== 62F --- 60F --- 60F --- 62F --- 60F

After Run ==== 128F --- 120F --- 179F --- 120F --- 126F

Note: The temperature of the axle shaft, between the pumpkin and the wheel, did not increase significantly, nor did the outside of the disc calibers.

I plan on making another 20 mile run and check the temperatures again.

I think you're OK on the brake rotors. Very slight drag is normal. Be sure rotors don't wobble, since that will increase drag. Both the rear axle and brakes will probably pick up some engine heat.

Could someone check their pumpkin temperature?

What is that large rectangular thing in front of your rear axle, where I would expect to see a cylindrical silencer??

Chris, that looks like he’s using a cookie sheet to keep the exhaust off the rear end for his temperature test.


Andy

Chris, I installed the sheet to keep the exhaust off of the pumpkin as Andy indicated.

I would appreciate if several T owners would check the temp of their pumpkin, either by touch or by a laser thermometer.

Bruce

I hope some will respond. I would also need the air temp when the pumpkin is checked. Thanks

Bruce

I sure would appreciate if several would check the temp of their pumpkin; that is by hand or laser thermometer and would need the air temp also.

Yours is the first post I have ever seen in 20 years on the forum concerned with a hot rear end. I really don’t think you have anything to worry about. You have one of the nicest T in existent. You did everything right. Enjoy driving it and stop worrying. If you allow yourself to become obsessed with everything that can go wrong on a T, you will never have any peace.

My car like many others is put away for the winter. I would be glad to measure the temperature if I was driving it. If you have the rear axle lube where it should be, you gave nothing to worry about.
Regardless, I will measure and document all driveline components in the spring.

The pumpkin temperature will undoubtedly rise if going up a long hill. In the spring maybe this will be a topic of interest.

Aet Mirtes

That rectangular object in front of the axle is where he keeps his suitcase. With his wife's luggage in the T, there is no room left for his suitcase.

I still am hoping several of the T owners who haven't put their cars away for the winter would check the temp of their pumpkin, either by touch or laser thermometer and would also need the air temp.

Bruce, Had mine out today air temp was 31* F and after about seven miles around town pumpkin was at 46*F. It was rather cool but when I'm out in the T it don't seem so cold. Jim

Jim, Thank you very much! This the type of information I need. I hope some others will do the same.

I am still hoping some of you T owners will check the temperature of the pumpkin, by hand or laser, preferably.

Art M, You said you would check yours in the spring.

How is the exhaust inside the car? That pan behind the muffler looks like it would direct the exhaust through the floorboards into the car?
Norm

The pumpkin will normally generate heat during operation. Some is from mechanical friction, and some is from fluid friction in the lubricant. Higher speeds will produce more heat, as will more applied horsepower, but the actual temperature rise will depend on many factors, such as ambient temperature, car speed, wind speed, how much engine heat reaches the axle assembly, type of lubricant, duration of trip, and more. If you're worried about excess friction, checking for any indication of abnormal binding when the axle is warmed up fully and listening for any abnormal noises would be a good idea, as would checking the lubricant for excess metal particles. Most axles will show some tiny metal particles in the lube, especially if the axle is new or recently rebuilt.

Most disc brakes, and especially older designs, will show a temperature rise when the car is driven, even if the brakes are never applied. Loose wheel bearings, calipers that lack some "float", warped discs, or sticky caliper pistons will increase heat and drag.
A T axle might be expected to have more axle shaft end float than a modern axle, and thus might cause disc brakes to run slightly hotter than normal. More end float might cause a little more pedal travel than normal, but probably would not cause any other issue.

Waiting for someone to check the temperature of their pumpkin.

I checked mine yesterday after a morning drive. My car also has the Sure-Stop disc brakes, which got used plenty. Temperatures measured using a cheap laser thermometer.

Ambient Temperature: 65-68 degrees
Differential Housing Temperature: 98-101 degrees

Thanks Derek, just what I wanted!

I hope several more guys (or ladies) will check the temperature of their pumpkin.