1974 GMC 4905 potential towing problem

chessie4905 · August 11, 2018, 03:37:47 PM

Pretty tight to pull driveshaft on a 4905. It is very short and passes closely through two bulkheads at an angle. I wouldn't want to do it unless it was over a pit.

luvrbus · August 11, 2018, 04:29:32 PM

Quote from: chessie4905 on August 11, 2018, 03:37:47 PM
Pretty tight to pull driveshaft on a 4905. It is very short and passes closely through two bulkheads at an angle. I wouldn't want to do it unless it was over a pit.

I wouldn't want to pull the shaft it is a heavy sucker with hump teen bolts that never seem to want to come out,and besides a tow company will not reinstall one

chessie4905 · August 11, 2018, 05:55:39 PM

The 4104 was a pain too. Every other bolt is a light press fit through flanges. Plus nuts were wired. You had to cut and remove wire, remove nuts, and use a brass hammer to drive out bolts. Much much easier after discarding drive shaft brake drum and shoes assy. Added maxi brakes instead.

dtcerrato · August 11, 2018, 07:22:42 PM

We're still running to old drive shaft brake on our 4104 with original brakes. Upgraded to an E10 application valve which put front & rear brakes on different cylinders on the common shaft. It stops on a dime with 9c change.

Geoff · August 12, 2018, 03:20:15 PM

On a V-drive you disconnect the driveline at the rear end U-joint where it connects to the rear end and slide it back towards the transmission and tie it up. Not at the flange.

chessie4905 · August 12, 2018, 03:38:20 PM

Even if they could disconnect drive shaft at u-joint. You can figure on buying a new joint. What are the odds of retaining all the needles? I'd have them pull axles. But everyone should have a set of hub cap off plates in their coach. Another advantage to grease packed rear wheel bearings, at least with GMC's

Geoff · August 12, 2018, 03:58:01 PM

I know what you mean about the needle bearings! The are suppost to take the caps off carefully so not to lose the needle bearings, OR duct tape the caps on.

luvrbus · August 12, 2018, 04:20:21 PM

I have tried it both ways it's easier on a 4905 to remove it at the flanges

Geoff · August 12, 2018, 04:25:14 PM

Quote from: luvrbus on August 12, 2018, 04:20:21 PM
I have tried it both ways it's easier on a 4905 to remove it at the flanges

If you do that, how are you going to keep the driveline from turning when the bus is being towed? I think it's time to watch TV with my wife and BBQ some steaks! Goodnight.

luvrbus · August 12, 2018, 04:35:37 PM

I don't under stand the question Geoff ,the drive shaft is disconnected when you un bolt the drive shaft flange from the differential flange

eagle19952 · August 12, 2018, 05:58:02 PM

Quote from: Geoff on August 12, 2018, 03:58:01 PM
duct tape the caps on.

Baling wire.
6010 7018 1/8 inch welding rod bent.
keeps the caps on for me.

chessie4905 · August 12, 2018, 06:52:28 PM

Yes if you remove them. Tow guy hammers on shaft to free caps because they've been on a long time. They finally pop off and hit the dirt. Needles still in place??? Does the tow guy care???

Geoff · August 13, 2018, 12:31:37 PM

Hi, Clifford. I thought you meant the flange at the transmission end. If the driveline has a parking brake drum that changes things.
Geoff

Ryker · October 18, 2018, 05:03:34 PM

Quote from: chessie4905 on August 08, 2018, 12:19:48 PM
4:27 ratio.74 mph@2400 with 315?80-r22.5. Probably 69@ 2150

I just realized I did not respond to this. My tire sizes are 12 R22.5 and I can cruise at 70 mph and only about 1800 rpm.