Theory on preventing frame cracks around steering box and panhard bracket (1 Viewer)

[jpoole]

After repairing and reinforcing frame cracks around the steering box on my 80 I have a theory on a relatively easy change that could possibly prevent this cracking from getting started, at least in more moderate use-case scenarios. The photos below illustrate the change that I think could be helpful, possibly as a prevention on non-cracked 80s. To cut to the chase though, I think that welding the engine side of the panhard bracked to the frame at the lower edge of the frame would stiffen and strengthen it's connection to the frame and possibly prevent the cracking that seems to start on the other side of the frame (tire side) below the steering box. I'm sharing this in case it's helpful to folks that are concerned about the cracking issue and as a way to possibly protect against cracks without adding plates/etc. which some folks may wish to avoid. The good thing is that with a flux core wire welder that doesn't have a gas nozzle you can get into the weld points below pretty easily with no disassembly/etc. making this a very quick/easy way to add some stiffening.

Here's a photo of where my 80's frame cracked and where I think this cracking typically starts even though it often migrates to the frame sides as things loosen and flex more under the steering box. The red lines trace the two cracks my frame had (the lower crack was partially repaired before). The green line shows where I've seen these crack on other 80s (via mud photos):

Here are photos that show the factory welds on the engine side of the frame where the panhard bracket mounts. The green dots represent the lowest weld point. The red dots show where I think adding welds would strengthen the connection and lower the stress on the other side where cracking typically starts. Note that the green dots are around the middle of the frame side which is the most flexible point of the frame and in my understanding explains why the stress if focused on the joint that typically cracks (shown above). I'm not sure why Toyota didn't weld below this mid-point but I assume that it was because of difficult access due to the crush tubes, though there may be other reasons? I don't think welds at the red dots would be enough for heavy wheeling with large tires but for stock tire size and mostly road use it may?

To my discredit I'll show the finished product of my repairs. The first repair (in picture 1 above) was hired out but I wasn't happy with it so decided to make the next repair attempt my first welding project. I bought a cheap flux core welder and added reinforcement plates inside and out, repaired the cracks on my panhard mount, welded the sections near the red dots and added a small corner brace to the panhard bar, etc. I didn't like putting so much heat into the frame with the plates but decided to weld it all since I had the steering box off already. The welds below are ugly and it's mostly because I'm not a good, or very patient, welder (or painter) at this point. Accessing the inner plate is also really difficult and it was spatter city in many areas

After years of working on the front-end of my 80 it's finally feeling stiff and tracking well as a result. I plan to add a bit more caster and then I think I'll be done in this area until the engine is out one day and I can grind/clean up the welds/etc.

For reference I used the plates below. They were delivered to my location in TN 10 days from purchase. The plates were $75 and shipping was $45.

80 & 105 Series Steering Box Chassis Repair Plates - Black Mamba Racing

Toyota Landcruiser 80 Series Steering Box Chassis Repair Plates

www.the4wdshed.com

 

[nukegoat]

Hmm

 

[BILT4ME]

After repairing and reinforcing frame cracks around the steering box on my 80 I have a theory on a relatively easy change that could possibly prevent this cracking from getting started, at least in more moderate use-case scenarios. The photos below illustrate the change that I think could be helpful, possibly as a prevention on non-cracked 80s. To cut to the chase though, I think that welding the engine side of the panhard bracked to the frame at the lower edge of the frame would stiffen and strengthen it's connection to the frame and possibly prevent the cracking that seems to start on the other side of the frame (tire side) below the steering box. I'm sharing this in case it's helpful to folks that are concerned about the cracking issue and as a way to possibly protect against cracks without adding plates/etc. which some folks may wish to avoid. The good thing is that with a flux core wire welder that doesn't have a gas nozzle you can get into the weld points below pretty easily with no disassembly/etc. making this a very quick/easy way to add some stiffening.

Here's a photo of where my 80's frame cracked and where I think this cracking typically starts even though it often migrates to the frame sides as things loosen and flex more under the steering box. The red lines trace the two cracks my frame had (the lower crack was partially repaired before). The green line shows where I've seen these crack on other 80s (via mud photos):

View attachment 2703249

Here are photos that show the factory welds on the engine side of the frame where the panhard bracket mounts. The green dots represent the lowest weld point. The red dots show where I think adding welds would strengthen the connection and lower the stress on the other side where cracking typically starts. Note that the green dots are around the middle of the frame side which is the most flexible point of the frame and in my understanding explains why the stress if focused on the joint that typically cracks (shown above). I'm not sure why Toyota didn't weld below this mid-point but I assume that it was because of difficult access due to the crush tubes, though there may be other reasons? I don't think welds at the red dots would be enough for heavy wheeling with large tires but for stock tire size and mostly road use it may?

View attachment 2703250
View attachment 2703251


To my discredit I'll show the finished product of my repairs. The first repair (in picture 1 above) was hired out but I wasn't happy with it so decided to make the next repair attempt my first welding project. I bought a cheap flux core welder and added reinforcement plates inside and out, repaired the cracks on my panhard mount, welded the sections near the red dots and added a small corner brace to the panhard bar, etc. I didn't like putting so much heat into the frame with the plates but decided to weld it all since I had the steering box off already. The welds below are ugly and it's mostly because I'm not a good, or very patient, welder (or painter) at this point. Accessing the inner plate is also really difficult and it was spatter city in many areas

View attachment 2703260


View attachment 2703259

After years of working on the front-end of my 80 it's finally feeling stiff and tracking well as a result. I plan to add a bit more caster and then I think I'll be done in this area until the engine is out one day and I can grind/clean up the welds/etc.

For reference I used the plates below. They were delivered to my location in TN 10 days from purchase. The plates were $75 and shipping was $45.

80 & 105 Series Steering Box Chassis Repair Plates - Black Mamba Racing

Toyota Landcruiser 80 Series Steering Box Chassis Repair Plates

www.the4wdshed.com

Just because there is not weld someplace does not mean it's not strong enough.

There's a thing called Heat Affected Zone (HAZ) where the surrounding steel changes in molecular structure and becomes brittle. This is typically where the next crack will appear.

Properly pre-heating the steel to be welded to the proper pre-heat temperatures (as stated in AWS D1.3 and D1.1), then doing an appropriate weld with a properly sized machine and proper weld will make a big difference.

The method of weld, grinding (if any) and material preparation BEFORE welding makes the most difference. Planning the welds (which is what Toyota did) allows for flexibility of the part with minimal fatigue. You should rarely ever weld to the edge of a part (unless sealing it is more important) because it creates stress risers in the manner the heat is pushed through the weld and the physics of how it all goes together.

We deal with this in the equipment we build and I have seen some interesting failures in my time and it always helps to evaluate why a joint failed.

Personally, I think this area of the frame could have been slightly thicker and then possibly stress relieved or peened to relieve the stress in that area and dissipate the stress risers.

Grinding ridges and sharp points (referred to as grinder strikes) increase stress risers in an area and can assist in a crack propagating along a given path.

If you want to help relieve some of your stress in that area, a big rosebud torch and heating the entire area to a bit of a straw color will alleviate that stress, then let it air cool.

 

[Delta VS]

Just added these to the site, going to be adding some additional pieces for directly bracing the upper panhard bracket as well. In case anybody prefers to order from the US.

Delta Vehicle Systems - DeltaVS Frame Supports - Weld It Yourself Kit

Frames crack, we fix

www.deltavs.com

 

[jpoole]

Thanks @BILT4ME I was hoping you'd weigh in on this.

It does seem like Toyota tried to avoid welding close to the corners on the frame if you inspect more broadly which make sense as that would help keep the corners of the box stronger and more flexible. They do get as close to the corners as the red dots in multiple places though which made me wonder why they didn't in this case. I think it's safe to say that the frame in this area and/or panhard connections are not strong enough from the factory given how common this cracking is, even on non-wheeled 80s.

I guess, based on your feedback and my suspicions welding near the red dots as PM is a bad idea and is likely to cause issues (hardening, stress risers) where there aren't any.

I'm thinking I need to learn up on heat treatment and do what you are describing to increase the chances that my repairs last. My ugly welds seem to be overloaded with stress risers

In the case, like on my 80, where the panhard bar tower is cracked and moving easily I'm less clear on what the best fix(es) are. Given my limited knowledge/expertise I decided to scour the internet to see what other folks have done in this area and then dive in as we have a long road trip pulling our popup camper scheduled soon. Online there are 3 or 4 variations on the frame/fish plates as the most common fixes in this area with reported good results, particularly from folks down under that seem to have a lot of experience with this repair. I tried to incorporate all of those that I could without covering up more than I had to so that I can keep an eye out for future cracks/rust/etc. I assume that some version of pulling the engine and possibly inner fender/etc. and then executing more careful dissection/reconstruction of the frame with heat treatment would be best... Cleaner welds would also be a real asset here! Maybe when the kids are grown up I can take my time and redo all of this.

 

[SNLC]

Good to see you used a fish plate. Vertical welds on a frame are a nono, especially on a high stress item like the panhard mount.

Cheers

 

[richardlillard1]

I had most of these cracks, at different times. After the second time, a gusset was installed which I now put on any 80 we are fixing. This is the one Kevin Patterson came up with for mine:

After seeing a frame cut up and getting a good look at how many different layers of steel are layered into this section of the frame, I don’t think it’s a lack of structure. It’s a lack of completed welds. I’m sure they had their reasons; ease of production, heat affected zones, access, etc., but the problem seems to come from the forces this area of the structure sees on a regular basis.

 

[BILT4ME]

I had most of these cracks, at different times. After the second time, a gusset was installed which I now put on any 80 we are fixing. This is the one Kevin Patterson came up with for mine:
View attachment 2703364

After seeing a frame cut up and getting a good look at how many different layers of steel are layered into this section of the frame, I don’t think it’s a lack of structure. It’s a lack of completed welds. I’m sure they had their reasons; ease of production, heat affected zones, access, etc., but the problem seems to come from the forces this area of the structure sees on a regular basis.

Not to mention the number of years and "cycles" these areas have seen on this age of truck.

I will admit, I welded my panhard bracket, but I suck at overhead welding and all I had was 6013 rod, and it leaves ugly-ass welds anyway. I will not parade my welds around anymore than I have to. I inspect, but I rarely actually weld anymore.

 

[Delta VS]

Good to see you used a fish plate. Vertical welds on a frame are a nono, especially on a high stress item like the panhard mount.

Cheers

Really? That's odd. I wonder why so many OEMs (including Toyota) have so many vertical welds on their chassis?

 

[BILT4ME]

Really? That's odd. I wonder why so many OEMs (including Toyota) have so many vertical welds on their chassis?

A repair weld is considerably different than a factory weld that can be done in position, with the proper tools and proper penetration.

Most of the time those "vertical welds" referred to are repairing an existing frame crack that started due to overloading, too many cycles, or damage.

Repairing it in a vertical line without it being in a correct position and done by inexperienced welders, using 110V buzz-boxes, will NOT result in a good structural weld.

I know you know that also, being in the fab business.

Most "professional" truck frame repairs I have seen have been diagonal in order to reduce the forces that caused it to break in the first place. They make a "Z-Cut" through the frame , then make the other end to match and the repair plates are oval, not square or pointy in any way.

 

[SNLC]

There are literally hundreds if not thousands of videos and posts across the internet in the custom vehicle, buggy/offroad and the hot rod world as to why you shouldn't do vertical welds on a frame.

Here is just one of those.

Vertical welds on frame rails???

www.pirate4x4.com

Lower stress items such as body mounts are not such a big deal. Frame splicing, fish plating, suspension brackets/mounts should not be welded vertically. Nobody needs to believe me, I don't have a degree in fab or welding but the info is out there if people care to research it themselves.

Cheers

 

[Delta VS]

1. Repairing it in a vertical line without it being in a correct position and done by inexperienced welders, using 110V buzz-boxes, will NOT result in a good structural weld.

2. Most "professional" truck frame repairs I have seen have been diagonal in order to reduce the forces that caused it to brake in the first place. They make a "Z-Cut" through the frame , then make the other end to match and the repair plates are oval, not square or pointy in any way.

These are the two important points here, I think.

#1 isn't going to be effected by the shape of a pre-emptive or repair bandaid, yes? Most folks are going to be going downhill even.

I think #2 is a very different situation where the frame is actually being cut, for a repair or to lengthen/shorten a frame where the frame is completely severed.

 

[BILT4ME]

These are the two important points here, I think.

#1 isn't going to be effected by the shape of a pre-emptive or repair bandaid, yes? Most folks are going to be going downhill even.

I think #2 is a very different situation where the frame is actually being cut, for a repair or to lengthen/shorten a frame where the frame is completely severed.

Yes, I agree.

Most also have no idea what we're banging on about........

Properly prepared joint, uphill vs downhill, in position..........

However, the lucky ones can at least throw a round or elliptical plate on it to keep away from sharp edges.

Hell, the stuff I used to do and see on the farm would give most CWI's a heart attack and cause them to freak out. Now I know better, but I still like to mess with them sometimes.....

 

[BILT4ME]

There are literally hundreds if not thousands of videos and posts across the internet in the custom vehicle, buggy/offroad and the hot rod world as to why you shouldn't do vertical welds on a frame.

Here is just one of those.

Vertical welds on frame rails???

www.pirate4x4.com

Lower stress items such as body mounts are not such a big deal. Frame splicing, fish plating, suspension brackets/mounts should not be welded vertically. Nobody needs to believe me, I don't have a degree in fab or welding but the info is out there if people care to research it themselves.

Cheers

If you read the attached link, you will find that no one answered Atomicjoe23's question.

It takes a metallurgist in the structural design of the welding to answer what he's asking. Probably could also do with a physicist to determine all the proper loading across a convoluted joint to determine all the loads.

For the most part, it is what I was talking about with the HAZ and controlling the weld interpass temperature so you don't overheat the area and cause a molecular change where you don't want it, or to be too cold and get insufficient penetration.

There is a reason that buggies and racecars use chromoly tube and it's all round. Structural integrity and strength per foot, based on the weight of the product. The cages are designed to be strong and protect, but have a ton of interference in the cabin, etc, but they are not practical in "everyday" automotive designs or for hauling like a truck.

Cost per fabricated pound is very high on a chromoly tube frame and it would drive the cost of a truck frame through the roof if they designed to carry those loads, so it's an economic decision.

 

[SNLC]

From what I have read chromoly is not used much in roll cages because of the special heat treating it takes to get it right. Again, I am no metallurgist. I researched this a lot though for a project we are doing and everything I read said stick with DOM.

Everything we do to a frame in my shop is not a fish plate, you can’t always do a fish plate. However whenever possible we use a fish plate and avoid vertical welds on a frame. We also try to use a long fish plate to distribute stress and loads across a larger area.

The early 80’s seem to have the most issue with the frame cracking around the steering box. Toyota put an internal gusset inside the frame at this location after the first few years. Not to say they still don’t crack but they did improve it.

Cheers

 

[leonard_nemoy]

The whole cracked frame thing seems very hit or miss to me. I can only think of a handful of times I have actually seen someone post up with this issue over the years on the forum. I know it is a real thing but I would expect it to be more common. I put 140,000 miles on my 91 with 35's. Lots of offroading and even a bad wreck with a hard hit to the hub and I never developed cracks.

My current 97 used to get the piss wheeled out of it on 37's at Sand Hollow for years and it also does not have any cracking issues.

I am not concerned enough about this issue to try and do anything to prevent it. If it does ever happen to a cruiser I own than I will fix it.

Don't fix it if it ain't broke!!!!

 

[DivByZero]

I have this crack issue on my 96 year, and this thread has made me realize fixing this properly is a lot more complex than I'd anticipated. From some of the people in this thread who know a lot more about welding and fabrication than me (IE, anything at all), what would you suggest is the best way to fix this, for the long term?

I want to keep my 80 for another 20+ years. I was just going to attack the crack with a welder, but now I'm reconsidering that. What's the best way to do a 20+ year repair on this? I don't want something that mitigates the issue for a couple of years, but makes a much bigger problem in the long run.

 

[Bludozer]

The early 80’s seem to have the most issue with the frame cracking around the steering box. Toyota put an internal gusset inside the frame at this location after the first few years.

'95-'97 supremacy confirmed.

 

[SNLC]

The whole cracked frame thing seems very hit or miss to me. I can only think of a handful of times I have actually seen someone post up with this issue over the years on the forum. I know it is a real thing but I would expect it to be more common. I put 140,000 miles on my 91 with 35's. Lots of offroading and even a bad wreck with a hard hit to the hub and I never developed cracks.

My current 97 used to get the piss wheeled out of it on 37's at Sand Hollow for years and it also does not have any cracking issues.

I am not concerned enough about this issue to try and do anything to prevent it. If it does ever happen to a cruiser I own than I will fix it.

Don't fix it if it ain't broke!!!!

Rolled my 91 2.75x, no cracks. Customers 90 HDJ81 got jumped, broke the steering box, bent front axle and trashed the suspension but no cracks and frame is true.

And those are the ones without the internal gusset.

I plan to fish plate it on one of my 80’s, the other one, meh.

Cheers

 

[SNLC]

I have this crack issue on my 96 year, and this thread has made me realize fixing this properly is a lot more complex than I'd anticipated. From some of the people in this thread who know a lot more about welding and fabrication than me (IE, anything at all), what would you suggest is the best way to fix this, for the long term?

I want to keep my 80 for another 20+ years. I was just going to attack the crack with a welder, but now I'm reconsidering that. What's the best way to do a 20+ year repair on this? I don't want something that mitigates the issue for a couple of years, but makes a much bigger problem in the long run.

Take it to a qualified fabrication shop, since you plan to keep it 20+yrs.

Cracks should be drilled on the ends before welding, says me the self taught welder.

Seriously though they should be and you could also open them up to a channel or bevel, then heat it up real nice, then weld it up and then fish plate over that. That is what we would do in my shop if you brought it to us for repair.

Cheers