I have a 96 XJS. I noticed something I had not seen before, rust.

Obviously the PO had run something over that scraped off the underbody coating and even managed to poke a hole in the underside! It occurs just behind the passenger side door, towards the rear wheel.

How do I handle this?

Can I use some naval jelly to remove the rust, patch the hole with some JB Weld, and then prime, and plastikote?

I'm assuming I don't have to go to a body shop for something this...hidden.

Any advice is appreciated!

 

Hi Vee,

Yes easy enough fix. You will want to clean off the surface rust first on the metal. I would try either a red scrub pad or a wire cleaner head that fits on the end of a drill. After you have cleaned all of the surface rust off then you will want to patch the hole in the metal. You can patch the hole many different ways from welding shut(if you weld you will need to set back needed interior carpets etc to keep a fire from starting) to JB weld type material ( the key is the make sure what ever you use you want to make sure the metal is clean and your patch will hold up and keep any moisture from getting through ). I would then apply a light coat of metal etching primer to the bare metal and finally apply a undercoat to seal off. I would do this as soon as possible but looks like a simple repair since on underside of floor so you do not have to make pretty or match color as if it were on the exterior upper body panels.

 

Thank you for the advice.

I am not a welder, so I will find some kind of compound I can set in there cold.

 

There's two sentences you don't see together too often!

Graham ( living in the 'Land of Rust" )

 

would you buy a car that has the rust ' covered up ' rather than repaired properly ??

its a slippery slope to the car ending up on the scrap heap....

do it right first time , it will ultimately cost less and last longer, and you will keep your good name

BB

 

Just to clarify a few things about rust. Rust is like cancer in that if you do not remove it all it can fester and grow and come back with a vengeance. Now, most of us will be exposed to two types or rust on our cars ( I say two types because even though rust is rust you will usually run into basically two different forms on your car ). The first is surface rust which is the easiest to deal with and get at (think of skin cancer) in that surface rust is easy to see and if caught and dealt with quickly it is not hard to get at and get rid off as it is on the surface of the metal. The second form of rust we can run into on our cars starts forming between layers of metal or from the inside out. The second form is the hardest to deal with and get rid of because normally by the time we see an issue like paint blistering under a glass molding or on our rocker panel the damage is much deeper and extensive then we realize. The second form is easier to find with a car that is driven in areas where there is salt used on the roads in the winter time or very wet climates like England.

Even though newer cars have much better e-coat protection on the metal coming out of the factory the facelift XJS cars can and will rust. It is all a matter of exposure of corrosives like salt or moisture. The reason I will not restore a car that has extensive rust in the 2nd form I talked about is because it typically is not cost effective to do so. Unless you are willing to spend the time and money to get at this type of rust to make sure none is lurking between layers of metal etc., well in my opinion you are just wasting your time. Think of a quarter panel that is starting to show rust at the lower edge either over the wheel well area or on the back lower edge. Unless you remove the outer skin of the exposed area(there by destroying the removed outer layer) and get to all the rust that is developing on the inner structure surface, the rust that you do not see and leave behind will continue to fester and grow. Some people will patch over rust like this but this is just hiding what you can see on the surface.

So Vee lucky for you the rust you are dealing with on your car is surface type rust. It was able to get started because the undercoating was compromised allowing bare metal to be exposed. Because a hole was punctured in the metal you will want to make sure the top side of the floor that was exposed from the hole is not compromised and starting to rust. It is always possible that the top side paint was damaged or broke loose and is starting to rust in that area also so make sure you check by pulling back needed carpeting and trim.

Hope this helps anyone who has not had to deal with much rust issues on cars and for those that have already had to you will be able to appreciate this statement: " If you are looking at buying a car (especially one coming from a area that is known to cause extensive rust issues on cars and you see signs of extensive rust issues-RUN-RUN-RUN " Nothing and I mean nothing can be harder to deal with and therefore more expensive then extensive rust issues on a car. Do not underestimate how difficult it can be to deal with this issue or you may quickly find yourself dumping money into a very deep hole.

 

The solution for me with a rusted floor pan in an old Datsun 510 was to sandwich the
floorpan.

Used rust converter on the inside after knocking off the loose rust, then laid layers
of resin soaked fiberglass to form a pan. Followed up on the outside in the same
fashion.

The result was a waterproof floor pan with the original metal sandwiched in resin.
This kept air and water from ever touching the metal in the future.

Stronger than original, and the pans could be hosed out without fear.

You will want to do this when it is *much* warmer than it is right now.

Resin that doesn't kick due to cold is a real pain to deal with.