Rustproofing the suspension

Yesterday I decided to raise the car, take a look at the suspension, with the aim to clean and coat it with a protective film. I had the sense to just take on the rear suspension for starters, lol.

I used AD2000, Corrosion Inhibitor and Lubricant. Didn't research that much, hey, it's what I had. For the most part I applied by spraying it (with straw extender) onto an old toothbrush, worked it in, and wiped around with a rag. For unreachable zones, and main bolts, I sprayed, but tried to minimize this method, to avoid an oil bath.

I wanted to deal with the main rear beam and everything welded onto it, the cup at the bottom of the spring, the shock connections, the trailing arm and the wheel bearing. I paid special attention to any welds/junctions, and made sure all the main bolts were cleaned and thoroughly coated.

I spent about 6 hours, and at least one hour dealing with infuriating fasteners on trim pieces, some that were near impossible to remove even when new, doubly so now that they're rusted to near garbage. Toyota REALLY could improve in this department.

Here's a pic someone took of the underside. I've highlighted what I dealt with yesterday, and some panels I took off for access. The circles are 10 mm (socket size) bolt locations, that were badly rusted, to the point I nearly rounded the heads backing them out. This is in west coast climate, very little salt on the road, garage stored, 4.5 years low mileage.

The arrows are fasteners holding wheel well "spats". Taking them off is pretty much mandatory, and they have a hopeless fastener: a bolt on the inside, inside a little seat, near impossible to get a wrench or anything on. The nut on the outside is a flimsy metal/plastic combo. And they were badly corroded, chucked them and replaced with aftermarket black nylon "license plate" bolts and nuts.

It's pretty much mandatory to take the wheels off too, for access.



I'll post a few phone pics in a bit.

A few condition pictures. Not bad, but this is garage stored, low mileage, wet coast.




This is the forward end of the trailing arm component:



Here's the bracket the (right side, looking towards front of car) wheel well spat connects to, the bolt goes inside it, spat (and paper fender liner on ours) goes over, then nut. Took a concerted half hour struggle to get the mother off. Rusted crap.



Reinstalled with nylon license plate bolt and nut:



Info:



Close to wrapped up:

 

Oh, the stump? That's my life insurance, lol.

 

Would galvanizing be a good sub, for the banned coatings. The open ended lug nuts I got from dealership, for Corolla steel rims i have with snows, have lasted good. A moot point, it is what it is...

The circled fasteners in the first, full view of underside, just holding on plastic shielding: another year or two and they would need to be drilled out, or removed with impact driver. And I'm not in snow belt, and low mileage.

You can see all the dinky screw fasteners at "bumper" edges, all their heads are total surface rust. One of the highlighted panels has one of those: it's coarse threads pretty far gone with rust. It screws into a bent metal clip pushed over a plastic trim edge. That clip also was pretty far gone.

So maybe any recent car is going to have similar fastener rust issues, or are there still good options, but they're cheaping out?

Did the front end suspension: more convoluted, not too bad. Found some more troublesome fasteners: the three 10 mm (socket size) bolts holding the front wheel well spats to another plastic underside piece. This time they were completely rusted: broke off a bolt head trying to back one out. It's not really a deal braker, you could remove the spat together with the connecting piece, if needed. Toyota could have just used permanent pop rivets there.

The spat from the outside:



And an interior view, the nuts welded to a metal strip. Comepletely rust bound:

 

I tried liquid wrench, then drill thru the center and a bolt extractor bit, on the one I snapped the head off. Hopeless, dubbed it one piece. It still holds in place.

Thumbs down again Toyo.

 

It's unheated garage. I've read with frequent driving an unheated garage is better. With infrequent driving a heated garage is better. We had next to no snow last winter, our winters in general are very mild, and only modest road salting happening.

The fastener portion on the inside is not at the lowpoint in there, and there's honking big drain holes, evident in the picture.

Yeah, I've managed to break off a bolt head on BOTH sides now, lol. Each side has 3 bolts, and the trim seems still quite secure with just 2 remaining. I tried liquid wrench (as I said) and after an extended time, very gently tried turning the bolt head back and forth. It finally broke off.

I might just do nothing, since the only way to remove the piece seems to be by breaking of the remaining bolt heads (easily done, lol). As you can see in the pic, there's some sort of plastic retainer clip holding the strap in position. It doesn't show on the underside, so I'm thinking it might be plastic-welded to the inner panel.

If I was going to remedy it, guess I'd get stainless bolts with oversized washers for the inside. It's frustrating poor design though, and the steel spec. is garbage.

 

I have a bunch of these, think I found them strewn all over a Honda dealership lot, years back. Maybe I'll try the drill and tap. For M6x1.0 would a 3/16" dia pilot hole be ok? I'd rather err on being slight oversize, these things are only holding plastic, and doing the tap in situ I'd hate if the whole piece started to turn.

I don't have a drill and tap set though, haven't done this since high school.

 

Thanks for all the info!

I tried drilling out for an extractor bit, finally threw in the towel. I was using a handheld drill. I have a drill press, was hoping to get the whole piece off the car, but there's one fastener type at back of wheel well that proved difficult to extract.

It's still very solid with 2 of 3 bolts, I'm going to treat it as a single piece, lol.

 

Me too, the nervousness about jack stands. You get used to it, but I finally decided to be sensible and quit getting used to it. Almost without fail now, I push this tree stump under first. If it were to collapse the stump would stop it. Sometimes it's impractical, too in the way, but whenever possible I do this.