E450 Front Axle Upgrade
I've been intrigued at the possibility of increasing the capability of our front axle and brakes. A visit to a CAT scale showed that the axle was at 99% of its 4600 pound capacity. So... a number of p...
Forum Discussion
UPDATES:
We've taken the coach on a few short trips and I liked how it felt but I couldn't say it tracked much better than before. So I tried two things:
1. Replicate Harvard's test for "truck alignment" based on degrees of Camber at hard over (about 25°) wheel cut. With his formula showing upper 4° left and just over 5° right, with fixed offset bushings, I doubt I can get much more Caster.
2. I had left Toe where my recently replaced Tie Rods had been set with the original axle. Decided it was time to re-check. My measurements indicated it was toe-in too far. My thought is that the old axle to crossmember bushings allowed it to toe-out, which I adjusted for. Then I didn't check it as part of the axle project. Just put the linkage onto the new parts with the same settings as with the old. I tried my shade tree/DIY toe adjustment, trying for just a little toe-in from neutral. Just took a test run yesterday. Just driving out of the neighborhood, the steering didn't have the "Too Light" feel that was there before. Before I even left the freeway on-ramp I could feel that the steering had a Center. Sure enough! For the first time in its history, the RV acted like it would prefer to go straight and not wander in another direction!
So... What is this Magic Toe Setting? Very imprecise but I tried to have the edge of the tread ribs 1/8" closer measured across the front than across the back. The hub centers are about 15" off the ground, but the tread can't be measured across the back more than about 11" off ground. So the measurements are from front and rear tread edges at a height of 11".
Turned out the steering wheel is about 10° to the right. Not sure I want to tinker with it right now. I know I'd want to twist the two adjust sleeves equal amounts in opposite directions but which way? Easy to end up backwards on stuff like this. Throughout the process I thought I was turning both sleeves equally, and the wheel had been centered when I started.
pauldub's comment - I'm satisfied that:
1. Adjustable Bushings listed as E350 WILL FIT E450.
2. Based on experiences here and conversation with John Henderson, I would not hesitate to install adjustable bushings. What I WOULD DO is be sure there was no grease or dirt on the surfaces of knuckle and bushing, use Loctite on the Pinch Bolt, and Torque Pinch Bolt to Specs, which I believe I read to be around 55-ft-lb. That's a lot for a fastener that size but I'd do it since I have permission... Maybe put some Loctite on the mounting surfaces, haven't thought that one through yet.
We've taken the coach on a few short trips and I liked how it felt but I couldn't say it tracked much better than before. So I tried two things:
1. Replicate Harvard's test for "truck alignment" based on degrees of Camber at hard over (about 25°) wheel cut. With his formula showing upper 4° left and just over 5° right, with fixed offset bushings, I doubt I can get much more Caster.
2. I had left Toe where my recently replaced Tie Rods had been set with the original axle. Decided it was time to re-check. My measurements indicated it was toe-in too far. My thought is that the old axle to crossmember bushings allowed it to toe-out, which I adjusted for. Then I didn't check it as part of the axle project. Just put the linkage onto the new parts with the same settings as with the old. I tried my shade tree/DIY toe adjustment, trying for just a little toe-in from neutral. Just took a test run yesterday. Just driving out of the neighborhood, the steering didn't have the "Too Light" feel that was there before. Before I even left the freeway on-ramp I could feel that the steering had a Center. Sure enough! For the first time in its history, the RV acted like it would prefer to go straight and not wander in another direction!
So... What is this Magic Toe Setting? Very imprecise but I tried to have the edge of the tread ribs 1/8" closer measured across the front than across the back. The hub centers are about 15" off the ground, but the tread can't be measured across the back more than about 11" off ground. So the measurements are from front and rear tread edges at a height of 11".
Turned out the steering wheel is about 10° to the right. Not sure I want to tinker with it right now. I know I'd want to twist the two adjust sleeves equal amounts in opposite directions but which way? Easy to end up backwards on stuff like this. Throughout the process I thought I was turning both sleeves equally, and the wheel had been centered when I started.
pauldub's comment - I'm satisfied that:
1. Adjustable Bushings listed as E350 WILL FIT E450.
2. Based on experiences here and conversation with John Henderson, I would not hesitate to install adjustable bushings. What I WOULD DO is be sure there was no grease or dirt on the surfaces of knuckle and bushing, use Loctite on the Pinch Bolt, and Torque Pinch Bolt to Specs, which I believe I read to be around 55-ft-lb. That's a lot for a fastener that size but I'd do it since I have permission... Maybe put some Loctite on the mounting surfaces, haven't thought that one through yet.
