[scorpian]

Looks like it has rusted due to water accumulation. Either ways you could either like others have mentioned grind it down to bare metal and treat it with a good marine grade primer and paint it with under chassis coating. You may also need to spray some rust converter just to be on safe side.

Whatever it is please take a decision wisely and get to the bottom of it or else this will spread fast.

[Aditya]

Thanks to Ilango Jupiter for sending this information in. Heartfelt gratitude for sharing it with other enthusiasts via this Team-BHP page!

Greetings.

I am Ilango Jupiter. My friend has voiced my concerns regarding the hole in the chassis on the forum.

Firstly, I would like to thank the team and the persons who have replied.

My priority is to save the truck and enjoy the ride. Hence, I need your valuable suggestions to repair it.

As stated earlier, I am not keen in expecting a so called favour from Tata Motors in replacing the chassis under warranty. Every warranty replacement is like Tata Motors doing a favour to the buyer. I am tired of asking them for favours.

For the sake of warranty concerns, I went to the Tata Motors dealer at sharp 9.00 am on Monday, 21 September. They checked the car and said that they will get back to me. I wonder how much time they need to say yes or no. It's been more than 36 hours since they have seen the car.

With my previous issues with warranty claims, I am in no mood to run after them. It should be the opposite and they must change the chassis under warranty, free of cost. Honestly, I never expect them to be so true to their warranty.

Regardless of their reply, I want to repair the chassis. After noticing the hole on Sunday noon, it's been two sleepless nights already. After all, it's my car and my concern.

Now, getting back to the repair business, as suggested by a few, I cannot leave the hole as it is. I am planning a reinforcement on the same. How should it be done and are there any special precautions to be taken for the welding? Waiting to hear from the experts.

I am not too keen in following up with Tata Motors. I want my vehicle to be fixed as quickly as possible.

After two days of doing my own research and inputs from a few friends and from the seniors in the fabrication shop of the company where I work, I decided to cut the area of the hole and gas weld a new piece. The brazing weld should hold for few years. Then spray zinc paint over it and completely repaint the chassis, do a yearly inspection and paint the chassis on a yearly basis.

Kindly send in your suggestions. I can't wait to get the chassis repaired. The car has run 58,350 km as of today.

[The Mechanic]

Dear Ilango Jupiter, the way I see it your options are as follows

1. Replace the chassis. This can be done and I have seen this done by both ASC and my FNG on vehicles whose chassis is damaged in accident or bend / cracked due to overloading. But this is going to be an expensive and time consuming path and the quality of work will depend on the workshop.I would not recommend it unless it is the only option.

2. Repair the chassis. First treat the rust then the hole, thoroughly inspect and clean the area affected inside and outside the chassis rail then rust proof it with suitable coating. Then weld thick metal plates to reinforce the area.

I would recommend you find a vehicle body builder and ask him to do the same. I am basing this on two things I have seen being done on old jeeps.


a. If the original chassis is beyond repair they get a used chassis , cut out the chassis number from old chassis and transplant it on the good chassis. This portion forms the first few feet of driver-side chassis rail.


b. One of common mods done on Mahindra "Jeeps" in my area is moving the rear leaf spring mounting points (perches) outwards from chassis and supporting new points on a structure made of welded steel plates.


I have seen both these vehicles overloaded beyond belief and still survive.


Follow this by generous anti corrosion coating and regular inspections at least for some time.


Also was this vehicle serviced at Tata ASC, if so they should have noticed this at an earlier stage.

[Aditya]

Thanks to Ilango Jupiter for providing this update:

I have left the vehicle at the local garage today for repair work. I don't have the patience to wait for Tata Motors. For them, it would be easy say yes or no. But they didn't say anything about it.

The local garage tinker inspected and arc welding appears to be the best choice. We don't have MIG/TIG welding and normal arc welding is the only available choice here.

Another update:

I have got some pictures from the local garage person. This is my first time with this local garage too.

For the safety of my family and myself, I quickly went ahead with the repair work using a reinforced MS sheet of 4 mm thickness with arc welding.

Another place behind this hole was also found to be kind of layered and I was told that it will hold good for the next 3-4 years. But I didn't want to take chance.

Work is still in progress and I will have a complete cleaning of the underbody and chassis done and paint it suitably.

[vigsom]

Originally Posted by vigsom

Drill a couple of low dia holes at the bottom of the chassis member

This will ensure no more water stagnates.

If you really wish to, reinforcement of the chassis can be done inside the chassis member by arc welding.

Originally Posted by Aditya

Attachment 2058686

Attachment 2058688

Immediate repair of the chassis that has been performed using a 4mm thick plate with arc welding is a great way to ensure that the chassis holds up long term.

You'll notice in the above attachments that a new plate that has been welded further down the chassis has a hole built in - I guess this is the lowest elevation of the chassis and this hole will ensure no more water stagnation.

Well done, Ilango !!!

Assuming that Tata had approved the chassis replacement, it would have been a massive job and all the original fit could have been disturbed.

[greenhorn]

So much for Tata improving their manufacturing. I had rust in my Indica subchassis during warranty and it was brushed off by the dealer as cosmetic and warranty replacement denied. By the 5th year the holes were clearly visible and by the 6th year I was advised that it was dangerous and had it replaced outside. It has been 7 years since the replacement and still no sign of rust, so the workshop clearly knows something about car manufacturing that Tata still hasn't figured out yet.


Details here https://www.team-bhp.com/forum/long-...ml#post3237009

[v1p3r]

Originally Posted by vigsom

Immediate repair of the chassis that has been performed using a 4mm thick plate with arc welding is a great way to ensure that the chassis holds up long term.

I agree. You've done the right thing - in fact 4 mm is overengineering, which I totally approve of! Just keep an eye on it for 1000 km or so, and you should be golden for the rest of the vehicle's lifespan.

[pawank]

Originally Posted by Vignesh_N/A

What is the best possible way to repair this? I know the technical way is to replace the chassis which I believe TATA won’t do.

The rusty part looks sketchy but a fabricator with decent work experience can fix that without compromising the integrity of the chassis. This repair job can be broken into two parts.
1. Cut the metal around the hole and reinforce it with new metal.
2. Remove the rust from inside the frame if it is just a surface rust, then paint it.

The area around the hole will rot in future if not treated properly. The best way is to remove that section along with that hole(marked with red in image). Cut a square shape area around the hole(marked with red), sand the area to make it smoother and then weld a new square shape metal patch in place of that square section.



Now you have to get rid of that rust from inside the frame(this must be done before welding the new metal patch). But the question is whether that rust is a surface rust or it has eaten the metal from inside. If that rust is just a surface rust then it can be remove by sand blasting or a metal brush. But if the inside section is rotten too then you have to cut and replace the whole section of that frame. This is a common practice in fabrication.

[PrasannaDhana]

Originally Posted by Vignesh_N/A

His primary concern is that, the hole may act as a stress concentration point and may fail under sudden cyclic loading. Doesn't give us a peace of mind once we know it is there.

I don't think that hole will be that much of an issue to be alarmed about. And reinforcement as discussed by the owner above seems to be the better solution here. Only in dreams will Tata replace the chassis in warranty. Whereas rusting is common more so when the vehicle is being used in coastal areas.

[AmitRavi07]

Did the owner find the actual root cause, i.e., how is water accumulating in that part, where does it come from? I don't think this part of the vehicle is designed to face water flow.