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| Re: Make a one-ton knuckle with the same mounting points as OEM [message #370712 is a reply to message #370711] |
Fri, 21 October 2022 20:51   |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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While I will have to allow that this should be pursued as some parts have already come short. I have to allow that I did notice the adverse camber of the two coaches I drove.
But please also include that I was a critical driver for 2 different OEs at different times.
A critical driver is not a test driver. The biggest difference is really writing skill.
A test driver drives production intent vehicles on predetermined test tracks often for hours at a time and frequently these tracks that are more like neighborhood streets with steel reinforced potholes....
A critical driver will be required to operate a test (often prototype or mule) vehicle in situations that are not at all normal but should be survivable. A five minute test can frequently require a report that is two or three pages long and has to be written for disposition (like in the case of a lawsuit - you wonder why I still write this way?) and must be completely clear and concise. These tests have to be "discoverable" in the case of legal actions. As such, if they find a critical driver that can effectively recognize and report a strangeness or non-linearity in the controls, he can expect to be employed to do so on an irregular basis. Manufacturers do try to correct these issues before a platform goes into volume production. The problem is that they have to find it first and prior to supercomputers this had to be done with hardware tests and reliable drivers. The onboard instrumentation could tell the engineers a whole lot, but there were (are) still questions that super computers can't digest.
I can relate several stories but I will require adult beverages and will never reveal the actual vehicles identification.
Now, if someone were to manufacture those knuckles or find an effective way to relocate the upper A-arm attachment at the frame, that would be new ball game and a very interesting one at that. Unfortunately, welding to the existing frame rails is forbidden due to past litigation. If you knew what validation went on for product liability confirmation, I expect that most readers here would never believe it.
Any of the known people that build critical systems for our coaches are at great risk. The only shield that the have is that most will not install such things and this is not an oversight on their part. If they sell you a kit and it is even missing a single part, they are providing and incomplete kit and so any liability then falls to the installer. If that installer cannot document that the kit provider's instructions were not followed to the letter, the provider cannot usually be held for anything more than the cost of the kit as provided.
Remember again that I used to be McCord's aftermarket gasket guy. This can also be a source of entertainment and then I can give you names and maybe part numbers.
I am not in any particular risk as most of Chaumière's front end was replaced when a lower control arm failed and dumped us into the I-95 ditch at 60MPH a couple of years back.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: Make a one-ton knuckle with the same mounting points as OEM [message #370716 is a reply to message #369412] |
Sun, 23 October 2022 19:06 |
bwevers
Messages: 597
Registered: October 2010
Location: San Jose
Karma: 5
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Senior Member |
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8 years ago, I did the one-ton conversion and didn't like the camber change and bump steer.
So I fabricated upper control arm mounts out of mild steel 3/16" plate and raised the mounting points 2 inches.
I measured from the existing upper control arm holes and extended them upward, with reinforcing in places.
Also, I used the entire upper control arm from the GMC truck to make it similar in function.
If you look at the one-ton truck, the upper control arm is inclined, front pivot is higher than the rear.
I tried to duplicate this geometry to make it the same as in the GMC truck.
I am not a professional welder, but so far no problems with my welds. It has worked for 8 years.
It also helped that the engine was removed so I could weld on the inside of the frame.
As I understand the GMC frame is made from mild steel 1080, so heat treating is not necessary.
I raised the upper control arm pivot 2 inches. The camber change was better. But I had an unexpected problem
with the toe change. When the front end went down under braking the wheels would toe-in.
To solve this problem I had to lower the tie rod ends 5/8 inch so that the toe change was minimal.
If you look at the stock GMC knuckle, the steering arm is lower than the one-ton.
So either the tie-rod has to be raised or the steering arm lowered.
I ended up using bump steer kit parts from Speedway Motors to lower the steering arm pivot.
The parts I used are heim joints with 5/8" hole and 11/16" left hand threads to mate with a
Chrysler tie rod sleeve. That threads into the GMC inner tie rod. I used the Speedway Motors
tapered tie rod end extension bolt with a spacer to lower the heim joint 5/8 inch.
The tie rod parts are shown below:
Regards,
Bill
http://www.gmcmhphotos.com/photos/data/6085/medium/DSCN1557.JPG
Bill Wevers GMC49ers, GMC Western States
1975 Glenbrook - Manny Powerdrive, OneTon
455 F Block, G heads
San Jose
[Updated on: Sun, 23 October 2022 19:08] Report message to a moderator |
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| Re: Make a one-ton knuckle with the same mounting points as OEM [message #370719 is a reply to message #369412] |
Mon, 24 October 2022 10:19 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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It's worked fine for 45 years, I see no need to change now. So maybe once every 100K I need to swap in a pair of hubs and bearings.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: Make a one-ton knuckle with the same mounting points as OEM [message #370720 is a reply to message #370716] |
Mon, 24 October 2022 16:32 |
mghamms
Messages: 466
Registered: March 2016
Location: Ware, Massachusetts
Karma: 2
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Senior Member |
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All the more reason to leave well enough alone.
bwevers wrote on Sun, 23 October 2022 19:068 years ago, I did the one-ton conversion and didn't like the camber change and bump steer.
So I fabricated upper control arm mounts out of mild steel 3/16" plate and raised the mounting points 2 inches.
I measured from the existing upper control arm holes and extended them upward, with reinforcing in places.
Also, I used the entire upper control arm from the GMC truck to make it similar in function.
If you look at the one-ton truck, the upper control arm is inclined, front pivot is higher than the rear.
I tried to duplicate this geometry to make it the same as in the GMC truck.
I am not a professional welder, but so far no problems with my welds. It has worked for 8 years.
It also helped that the engine was removed so I could weld on the inside of the frame.
As I understand the GMC frame is made from mild steel 1080, so heat treating is not necessary.
I raised the upper control arm pivot 2 inches. The camber change was better. But I had an unexpected problem
with the toe change. When the front end went down under braking the wheels would toe-in.
To solve this problem I had to lower the tie rod ends 5/8 inch so that the toe change was minimal.
If you look at the stock GMC knuckle, the steering arm is lower than the one-ton.
So either the tie-rod has to be raised or the steering arm lowered.
I ended up using bump steer kit parts from Speedway Motors to lower the steering arm pivot.
The parts I used are heim joints with 5/8" hole and 11/16" left hand threads to mate with a
Chrysler tie rod sleeve. That threads into the GMC inner tie rod. I used the Speedway Motors
tapered tie rod end extension bolt with a spacer to lower the heim joint 5/8 inch.
The tie rod parts are shown below:
Regards,
Bill
http://www.gmcmhphotos.com/photos/data/6085/medium/DSCN1557.JPG
1977 Kingsley 455 as stock as it gets except lots of Ragusa parts
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| Re: Make a one-ton knuckle with the same mounting points as OEM [message #370721 is a reply to message #370719] |
Mon, 24 October 2022 21:06 |
rickmike
Messages: 252
Registered: September 2011
Location: United States
Karma: 0
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Senior Member |
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jhbridges wrote on Mon, 24 October 2022 11:19It's worked fine for 45 years, I see no need to change now. So maybe once every 100K I need to swap in a pair of hubs and bearings.
--johnny
Parts worn out and replacement parts harder to get, LCA cracks, torsion bar socket cracks and hex 'wear', frame rust, better brakes, better more easily replaced bearings, better suspension geometry, replacement parts readily available and the best of all better suspension engineering than 55 years ago with no bean counter changing the engineer's mind.
Plus I had a Suspension Expert to guide the project.
Rick M.
1974 26' Canyonlands
aka "The General"
Clinton, TN
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