Under sealing

Hi all Looking to underseal my jimny pressure washed all off this morning going to let fully dry but not sure if I need to treat the surface rust first or can I go straight over it with dinitrol or something like that also not sure what parts I should not put underseal on any advice would be great thank you dawn

Well I pretreat the rust so drying now what do you all recommend for which underseal to use I was going to use dinitrol.many thanks dawn

I would just use a wax over everything you can see with the exception of the exhaust, engine, wheels and brakes. Dinatrol / waxoil etc will be fine.

Cremator1 wrote: Well I pretreat the rust so drying now what do you all recommend for which underseal to use I was going to use dinitrol.many thanks dawn

This is a topic that has been raised before.

Have a search, and you will find a few choices.

Personally, I am going to use Bilt Hamber, Dynax UC, and Dynax S-50.



Steve.

Hi scimike ok thank u do I need to do in the engine bay or will that be ok

I personally would stay away from the engine bay, mainly as when I did mine I sprayed it on using a Shultz gun, it throws it everywhere.
So avoid things that get hot or rotate.
Axles, shocks, training arms and every panel underneath you can see etc are all ok to do.
Also if you can get some in the box sections of the chassis and body mounts. The drain holes make perfect access points, but just make sure when you have finished they are not blocked with wax.
Don't forget the front body mounts and just under the headlamps.
It's a messy job, so park over ground you don't care about or use a sheet to cover the floor.
Also have a good laugh at yourself when you have finished, you will look like the underside of the Jimny.
PS yours is not bad in the photos, wax should protect it nicely.

GEN4 owners have a look at the pictures of the surface rust on the welds etc, these are the locations you will see rust first, some visable on GEN3s I have seen at just over 12 months old. Hope the GEN4 is better, but the pictures are a good example of what to look for.

Hi ok great thank you yes will be using a compressor can you coat the prop shafts .yes mine not to bad at all but thought I would do it before it gets to bad.many thanks dawn

As far as my current knowledge about rust combat goes, the rust should be 100% eliminated first, either mechanically (sand blasting) or mechanically + chemically (scraping / wire brushing and then "painting" with a rust converter chemical).

Only afterwards it makes sense to apply any protective coating.

Apart from that, all "endangered" welds should also be coated with a polyurethane sealant (through a caulking gun) before any additional layers are applied. As you can see from the pictures, the welds are the most vulnerable points which start to rust first.

Applying any coating over "live" rust carries a high risk of being counterproductive in the long term.
In theory, insulating the rust from oxygen will "pause" it. However, as soon as the insulation diminishes in any way (delaminating, cracking, etc.), rust will get a super boost unseen underneath.




I wrote more about all this in the corresponding wiki article


I do not claim to be a definitive authority on this highly controversial topic in general - I am only trying to assemble the best practices from a myriad of false ones worldwide.

Hi guys thanks for the input just waiting on stuff to be delivered next week