Pinion leak and play - Dana 70 Dually - '97 Crestline Ambulance.

[Bikersmurf]

Pulled both axles out 6”, pulled the diff cover, pulled out the carrier, and removed the pinion gear out the back. After repeated trial and error adding extra shims I was able to bring the pinion bearing preload down below 30 inch pounds. Specs seem to be 17-30 inch pounds. At first it was slightly over 30 inch pounds till after I had spun it a few times and now the torque is just below 30 inch pounds… right on target.

I reassembled the diff, free play for these used gears is 9 thousandths (which is to the loose side of the 5-9 thousandths range), gear pattern is still good, all closed up, filled with oil and additive.

So far I have only gone for a short jaunt on the highway. I didn’t realize that the diff was making any noise, but the rig is quitter, and it feels tight.

I’ve not driven it on the highway enough to know for sure, but the cruise control surging when “coasting”. Time will tell for sure.

 

[Bikersmurf]

Now that the diff is back together with new bearings, the Ambo feels smoother when driving and it is also quieter too.

These bearings were living on borrowed time.



The guts of the differential:

LSD by whatever name.

 

[iggi]

I’ve done some further digging. It looks like disc Sterling 10.5 van axles use the same e-brake shoes as their truck counterparts. Logically, I could then use Van rotors to get the 8x6.5” spacing. The unknown variable is if Sterling van discs could be fit onto either the front of a Dana 70U hub.

I did a similar conversion when I mounted ‘79 Blazer rotors and callipers onto my Fj45 axle. Never had my Fj40 stopped so well before… which leads me to believe four wheel disc brakes would be great… time will tell.

Since 65% of the weight is on the rear wheels there is room to improve its braking performance.

The rear axle on mine has discs and is a Dana 70. I've been pretty happy with their performance.

 

[Bikersmurf]

The rear axle on mine has discs and is a Dana 70. I've been pretty happy with their performance.

The drums have been alright, but every once in a while I have to manually adjust the auto adjusters and the drums will probably be shot by the time the second set of shoes wears out.

I've been extremely happy with the 4 wheel disc brake conversion on my Landcruiser. Never having to adjust brakes, no brake fade, and excellent performance are things I miss with the ambo. I also like that its first set of used rotors lasted 100k miles.

I can't say the same for the ambulance... it seems to eat rotors and shoes.

 

[Peter_n_Margaret]

My OKA motorhome weighs 6.5T on the road and has 4 wheel discs on Dana 60 at front and Dana 70 at the rear.
The brakes are superb and discs and rotors seem to last "forever".
Cheers,
Peter
OKA196 motorhome