Rust on rear hatch handle

Yes, they salt the roads when there is accumulation. They pretreat with chemicals before. I think you're right about the small batch of inferior (not painted right) parts. I would have never checked that if it wasn't for your post.

 

Could you coat it with (wait for it) boiled linseed oil? Be careful not to spill over onto the rubber of the hatch opener component; use a fine brush at the bordering edges. That might "muddy the waters" though, if you're lobbying with dealership for replacement.

 

I somehow knew you are going to suggest that. LOL You could. But it is such a small area, without removing the part, avoiding to paint the rubber part is difficult. Also, since this is the area that get touched by your finger tips (nails) often when you grasp the hatch handle, coating may not stay long time. Furthermore, I think the actual metal back plate is much bigger piece than what is exposed. Painting the exposed part only may not resolve the rusting on the internal hidden part.

 

Yeah, they ideally need some hard plastic replacement part, or maybe something hot-dip galvanized and rubber coated.

 

Exactly why it needs to come out to be dealt with. Plus, it's just easier that way.

 

Hopefully that's possible, but it may actually be embedded in the carbon fiber as reinforcement.

 

Could be. So far, I haven't seen any reports of anyone getting access to it.

 

Our 2017 has a plastic hatch handle backing. (direct link in case it doesn't show)

 

Prius or Prime?
The carbon fiber hatch of the Prime may require a metal cross bar at the handle for reinforcement.

 

My 2012 Prius v has a rubberized cover on the hatch handle. So Toyota knows how to prevent rust there. The rubberized cover does not want to lift up when I tried to check for rust under it, and it still picks up a lot of road grime. It almost looks rusted, but it feels like flexible rubber covering the buttons and down the side facing backwards. I don’t see any rust in that gap where the rubberized cover ends towards the bottom of the picture. The opening looks smaller than the Prime hatch handle opening, and there are no plastic parts around the opening like the ones I took off the Prime to take pictures.

 

The material of the hatch around the handle is going to effect what the handle is made of.
Prius Prii had a metal hatch. The handle and its surround part exposed to the elements is very likely just plastic. The material of the hatch itself, properly painted metal, is supporting the plastic bits.

Carbon fiber is strong, but it doesn't behave just like a metal. Steel and aluminum have give to them. Application of a force, say from pulling on a handle, will cause the metal to flex a little, and then pop right back to original. Carbon fiber is more rigid; it doesn't flex like the metal. Though tiny, the repeated application of force from the hatch handle to the hatch could lead to cracking.

The metal backing that is rusting on the Prime appears to be unique to it, and my guess is that it to reinforce the area the handle mounts too in order eliminate the risk of fatigue cracks in the carbon fiber. Proper coating or painting would protect the steel piece from rusting. The issue is because of a manufacturing defect that lead in improper painting, or the engineers underestimated how much road salt could reach the spot. Considering how Japan doesn't use road salt, I think the latter has good odds.

 

I think it is the former not the latter, due to the fact that it does not happen on all Primes.

 

Stainless fasteners are very prone to galling, so not very production or service friendly. Even with a stainless fastener, if it goes to carbon steel the carbon steel with rust anyway.

I suspect that Toyota already does a hot dip coating on the chassis prior to paint. The white metal chassis are normally tank dipped in a primer/preservative after fabrication and before final paint.

Rust proofing coatings can be very problematic. In NW NY, they have problems where people get a hard coating sprayed on the underside of the car and all this does is trap the salt and corrosion is quite fast. Looks good on the surface, but pull off the coating and the frame is junk. A more flexible coating like Fluid Film is useful - I use it on wheel hubs where the aluminum wheel mates to the hub, on brake bleeders, etc. It puts a thin film on, then that gets coated with dirt and protects the coating. When you wipe this stuff on in a few years, the metal underneath is pristine.

Here are a few videos from a shop in upstate NY - this mechanic deals with rust daily - those cars get hammered by salt.

 

Yeah I watched that first one, agree.

I've been using boiled linseed oil, brushing it on. Worked surprisingly well.

Spray application of Liquid Film looks very effective though, especially for getting into corners, things like the 3rd gen trailing link on the solid rear axle for example.

 

I got the Fluid Film idea from his YouTube videos. and the stuff works great. It's a lanolin product, non-toxic, non-corrosive. About $10 a can where I live.

I spray it on my 35 year old chipper/shredder as well.

 

I went out an looked at my Prime (2018, build date 08/18). Bought new in CA Jan 2019, driven home through salt and snow, went through the rest of the winter here in Nebraska.

The black bar is definitely metal, and the trim housing around it is plastic. Mine had a small amount of crud along the edge of the metal piece, which I greenied clean and then treated the piece with Fluid Film. I'll see how well that protects it.

As found after wiping with my hand:



After scuffing with the greenie:


After spraying Fluid Film (takes a while for this stuff to harden up a bit):

 

This is our Prime. I should have been more clear about that. I can no longer edit the original post.

 

Mine is rusted on top right corner too. My next 16k km maintenance (in about 2 months) will ask them about warranty coverage/repair. I got the car last year August 2018 so only 1 winter and is already rusted

 

Here is dealer fix for the rusted back metal plate of the hatch handle. I had to pick my car up after the service hour and did not have a chance to speak with the tech to ask exactly what the body shop did. But looking from the result, it does not look like they have actually taken off the part to paint it. It does not look like a professional paint job. What do you think?

The BEFORE pic is found on the comment #57 Rust on rear hatch handle | Page 3 | PriusChat