Author Topic: 87 R10 Cracked Frame Repair @ Steering Gear  (Read 28216 times)

Offline bd

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87 R10 Cracked Frame Repair @ Steering Gear
« on: May 19, 2012, 01:50:26 PM »
This thread is an afterthought, so not a consecutive record of images.  No "before" pix, but suffice it to say, "It was awful!"  The gearbox pivoted greater than one-half inch away from the framerail and was barely retained by two of its four mounting bolts.  :o

The failure generally occurs as the steering gear pivots back-and-forth around an axis intersecting the top rear and lower front gearbox mounting bolts, tincanning the frame.  Crack-out of the frame is always exaggerated around the top front and lower rear gearbox bolt holes.  Interestingly enough, cracks propagate along nearly identical paths from vehicle-to-vehicle.  Frame cracking around the steering gear mount is worsened by the installation of larger tires, because of the increased force transferred to the frame as the gearbox overcomes greater resistance and leverage caused by increases in width, diameter and mass of the steer tires.

I began by clamping the frame back into its original shape and position.  Drilled 1/16" through holes at the end of every crack to keep them from propagating further.  V-grooved the full length of each crack to a depth of ~1/8" (or ~2/3 of the way through the 3/16" frame).  Tack welded the ends and intersections of the cracks, then welded each for full penetration.  Cleaned the inside of the frame and welded the back side of each crack, then dressed the weld reinforcement down to the original surface to restore the frame's integrity and appearance.

Next step was to hammer form a Warrior Products #899 1/8"-thick frame reinforcement plate to exactly fit the contour of the framerail, and then coat the plate and the frame with weld-through primer.  In addition, I fabricated and welded 1/8"-thick reinforcement onto the inside of the framerail around each of the four steering gear mount bolt holes.
« Last Edit: April 26, 2016, 11:24:57 AM by bd »
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline bd

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Re: 87 R10 Cracked Frame Repair @ Steering Gear
« Reply #1 on: May 19, 2012, 02:05:13 PM »
Next step was to tightly clamp and weld the fishplate to the outside of the frame and weld a second reinforcement plate along the length of the framerail lower flange below the gearbox (part of the Warrior kit).  Then I dressed it all down, primed and painted it.

I replaced the center crossmember, as well, since the PO used it as a tow hook and bent it beyond straightening.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline bd

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Re: 87 R10 Cracked Frame Repair @ Steering Gear
« Reply #2 on: May 19, 2012, 02:13:43 PM »
Since I didn't want to revisit this failure in the future, I decided to address the cause of the tincanning and stabilize the steering gear mount.  So, I fabricated torque arms for the steering gear mounting that rigidly bolt to the gear through the frame and anchor to the front crossmember at its center.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline bd

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Re: 87 R10 Cracked Frame Repair @ Steering Gear
« Reply #3 on: May 21, 2012, 12:37:17 PM »
Torque arms installed...
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline sonicbluezx3

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Re: 87 R10 Cracked Frame Repair @ Steering Gear
« Reply #4 on: June 20, 2012, 09:37:59 AM »
Nice. How do you tell your frame is bent without removing the gear?
1986 Chevy K10 w/ 1983 Cab, 1984 Bed, 1987 Doors and a 6.2 Diesel Swap w/ 700R4 Trans. Truck body completely re-done between 2010 and 2012.

Offline bd

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Re: 87 R10 Cracked Frame Repair @ Steering Gear
« Reply #5 on: June 20, 2012, 09:55:06 AM »
This project was aimed at repairing cracks in the frame that radiate from the steering box mounting bolt holes, which is a common occurrence.  You can check for cracks by carefully looking for telltale rust tracks and "radiating lines" on the inside of the frame rail.  To check for bent frames requires measurements, unless distortion is obvious.  Repair of 4x4 frames is similar, but the torque arm braces are different.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline whit

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Re: 87 R10 Cracked Frame Repair @ Steering Gear
« Reply #6 on: February 17, 2017, 08:33:42 AM »
Rich,
     I've been admiring your work in the attached pictures to this post.  I am in the process of repairing my 1979 Chevy C10 2WD frame.  Do you know of anyone that offers a steering box brace for the rear 2 steering box bolts for 2WD?  The brace in your pictures that you made for the 87 4WD looks great and is what I'm looking for.   I have repaired my frame cracks, I'm currently working on the Warrior side and bottom 2WD plates to get them to fit the frame, and plan to use the front Autofab brace for the front 2 bolts.  I would really like to also use a brace for the rear 2 bolts since the worst damage to my frame occurred at the rear lower bolt hole.  Both front bolt holes also had numerous cracks, but the rear was far worse and actually had a chunk missing.  I'm guessing I'm going to have to make a brace for the rear like you did since it appears that no one makes such.  Did you use 3/16 material?  Thanks for your detailed excellent coverage on this topic and the pictures.  You do excellent work. 

Offline 1967KaiserM715

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Re: 87 R10 Cracked Frame Repair @ Steering Gear
« Reply #7 on: February 17, 2017, 11:28:20 AM »
His pictures look like a 2wd truck.

 Off Road Design makes steering box braces and rear shock mount braces, for both 4wd and 2wd.

Sent from my LGL34C using Tapatalk

Current Vehicles:1985 GMC K10(Daily) 1991 GMC K2500(Daily) 1975 Beetle(not running) 1985 Mercedes 300D(not running) 1952 M35    1967 M715(not running)
 1986 Chevy K30(under repair)

Offline ehjorten

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Re: 87 R10 Cracked Frame Repair @ Steering Gear
« Reply #8 on: February 17, 2017, 01:48:55 PM »
I did this to my '91 Crew Cab, but I returned the reinforcement plate.  The forming on it was so horrible, and I did not want to try and beat the crap out of it to try and make it fit.  I just drilled out the ends of the cracks and v-notched them like you did, welded them up and ground them down.  I added the steering box braces, but modified them slightly for better oil cooler line clearance.  I have had them on for about 6 years and the truck is lifted 8" with crossover steering and 35" tires.  No new cracks!
-Erik-
1991 V3500 - Gen V TBI 454, 4L80E, NP205, 14 bolt FF, D60, 8" Lift on 35s
1977 K20 Silverado - 350, THM350, NP203, 14 bolt FF, D44, Stock Lift on 31s
1969 Chevelle Malibu Sport Coupe - EFI350, THM350
1968 Chevrolet Step-side Pickup - 300HP L6

Offline bd

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Re: 87 R10 Cracked Frame Repair @ Steering Gear
« Reply #9 on: February 17, 2017, 09:26:11 PM »
Rich,
     I've been admiring your work in the attached pictures to this post.  I am in the process of repairing my 1979 Chevy C10 2WD frame.  Do you know of anyone that offers a steering box brace for the rear 2 steering box bolts for 2WD?  The brace in your pictures that you made for the 87 4WD looks great and is what I'm looking for.   I have repaired my frame cracks, I'm currently working on the Warrior side and bottom 2WD plates to get them to fit the frame, and plan to use the front Autofab brace for the front 2 bolts.  I would really like to also use a brace for the rear 2 bolts since the worst damage to my frame occurred at the rear lower bolt hole.  Both front bolt holes also had numerous cracks, but the rear was far worse and actually had a chunk missing.  I'm guessing I'm going to have to make a brace for the rear like you did since it appears that no one makes such.  Did you use 3/16 material?  Thanks for your detailed excellent coverage on this topic and the pictures.  You do excellent work.

Thanks for your kind words.  My 1987 half-ton is, in fact, a 2WD.  As you have already discovered, both AutoFab and ORD manufacture similar single torque arm kits for 2WD GM trucks.  I expect that both brands attach on the leading side of the forward cross member to increase rigidity at the steering box front attachment.  I say this, because both appear to lack the necessary spacer to clear the brake combination valve and its piping; call them to verify.  Unless you're running tires greater than 31" tall, a single torque arm should be adequate on a 2WD when used in combination with a properly fitted Warrior semi-glove kit (frame face and lower flange), especially if you added supplemental reinforcement inside the frame.  If you insist on adding a redundant torque arm to the steering box rear attachment bolts, you may need to fabricate it, as I did, from 1/4" - 5/16" mild steel plate.  But, actual benefit is probably more to personal preference and pride than need.

IMHO - If/when choosing to "sandwich" the framerail with welded reinforcement, to avoid stress risers and subsequent cracking, the ends of supplemental reinforcement should be scalloped or arcuate, not square cut.  In addition, reinforcement plates should not terminate at the same location, inside and outside of the frame.  Ends should be staggered, so as not to create an abrupt change in frame rigidity, which can eventually cause fatigue and culminate in renewed cracking.

For supplemental reading that generally pertains to your project, click on the links in 87 chevy cracked frame from steering box fix.

His pictures look like a 2wd truck.

 Off Road Design makes steering box braces and rear shock mount braces, for both 4wd and 2wd.

I don't much care for the ORD rear shock supports.  Although they may add sufficient rigidity to the upper shock mountings to slow tincanning of the framerail. they primarily control fore-aft and axial (in-out) motion of the upper shock pin, whereas, the greatest damage to the frame results from the up-down oscillation of the shock as it leverages the shock pin and distorts the frame.  I much prefer an upper mount that will control motion in all axes and disperse the energy over a broad area of the frame.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline 1967KaiserM715

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Re: 87 R10 Cracked Frame Repair @ Steering Gear
« Reply #10 on: February 18, 2017, 08:35:36 AM »
I liked your rear shock braces more, but for those without any fabricating skills, a little is better then nothing. I am working on a set for my own truck-I did kind of copy the front braces, but have since decided to try and add to and beef them up a little more.

apparently the only pic I have loaded-1/4" mild steel was the end product.


http://forum.73-87chevytrucks.com/smforum/index.php?topic=31725.msg266776#msg266776

reply #5 has some good pictures. These two topics should find their way into the technical pages.
Current Vehicles:1985 GMC K10(Daily) 1991 GMC K2500(Daily) 1975 Beetle(not running) 1985 Mercedes 300D(not running) 1952 M35    1967 M715(not running)
 1986 Chevy K30(under repair)

Offline whit

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Re: 87 R10 Cracked Frame Repair @ Steering Gear
« Reply #11 on: February 18, 2017, 09:14:58 AM »
Rich, thanks for the detailed reply.  You're correct: both brands of steering box braces are for the front of the cross member and attach to the front 2 steering box bolts.  As far as I know, no one makes a 2WD rear bolt steering box brace.  They are available for 4WD but not for 2WD.  Thanks for the plate thickness details on how you made your steering box brace for the rear 2 bolts, I'll probably make one myself.  My tires are 28" tall P27560R15.  I would rather over brace things rather than going thru this repair a 2nd time with the plate welded on the outside of the frame. Also, I couldn't figure out a good way to plate the inside area of the frame since the cross member comes right up to the frame rail on the inside and the frame rail is not flat in the bolt hole area, I was thinking maybe to bolt up a spacer to the frame and weld a plate to the spacer and frame?  Could you describe how you did yours?  Did you use a single plate for all 4 holes or one for the front 2 and another for the rear 2 bolts?  Also, thanks for the comment on the rear shock braces.

Offline bd

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Re: 87 R10 Cracked Frame Repair @ Steering Gear
« Reply #12 on: February 18, 2017, 09:49:50 AM »
...I couldn't figure out a good way to plate the inside area of the frame since the cross member comes right up to the frame rail on the inside and the frame rail is not flat in the bolt hole area, I was thinking maybe to bolt up a spacer to the frame and weld a plate to the spacer and frame?  Could you describe how you did yours?  Did you use a single plate for all 4 holes or one for the front 2 and another for the rear 2 bolts?...





The upper image details the challenge presented by the uneven shape of the framerail.  I actually used four ~3/16" thick pieces inside the frame.  The lower image shows two plates shaped to fill above and below the "hump" between the front gearbox mounting bolts to help disperse stress.  Notice I avoided the radius of the flange-to-framerail face to help allow for frame flex without over-concentrating stress into the flange.  In addition, I was careful to not interfere with adjacent mounting holes for bumper brackets and the like.

For the rear gearbox mounting, I shaped a spacer to fill the cavity and closely hug the radius surrounding the lower bolt hole, then welded it into place.  I took a similar approach with the upper bolt hole, again avoiding the flange-to-framerail face radius.  Poor access made welding the upper plate a miserable task.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline fiddler

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Re: 87 R10 Cracked Frame Repair @ Steering Gear
« Reply #13 on: July 15, 2020, 12:17:42 AM »
You guys are blessed with those skills.  I have a 1974 chevy C10 stepside.  I had to pay for a welding job and repair kits and the removal and replacement of the steering gear box, but money well spent.  The truck drives like brand new now. 
Ricky