How to repair John Deere cab roof

Tony M · Oct 28, 2013

Unfortunately today I was watching my MMM close to a tree trunk and failed to notice that the roof was pushing hard against a rough knarled tree branch.

The tractor is a 3720 cab and the damage is to the front lip of the roof, just above the rhs worklamp. It's a combination of a dent, scratch and split and the total damaged area is about 1 by 4 inches.

It's only cosmetic and obviously not bad enough to warrant a new roof. So I'd like to repair it myself, but might use a professional alternative such as one of those mobile services that repair similar damage on car bumpers - I trust you have those in the US?. I'm not sure, though if the roof is made of the same plastic as car bumpers.

So I'd be really grateful if someone could tell me what the roof is made of and what sort of filler/binder would be suitable to stabilize the area prior to sanding it off and painting it.

Sorry, no photos yet - too embarrassed and annoyed with myself today. Might try tomorrow.

Regards
Tony

jenkinsph · Oct 28, 2013

I think you are on the right track using the car bumper repair materials. I tried it several years ago to repair a hood on a Deere lawn mower hood and it worked well enough. Bought a small kit for about $30 (US) at an automotive paint store. Enough material to repair a few dings on grandma's car and fix the mower.

Scooby074 · Oct 28, 2013

Urethane bonding adhesive like bumper repair and some mesh to back it up on the inside would likely work

Or fiberglass on the inside.

Bodyfill, sand and paint the outside to make it look "good"

bigblock · Oct 29, 2013

I bought my tractor used and it had a damaged cab roof when I first saw it. Left front and the work light were smashed. At first they told me that they would replace the roof but then discovered that a new cab roof was over $4000! They sent it out to a body shop that repaired the damage. I have no problem with it. You would never know that it was ever damaged. Sounds to me like you shouldn't have a problem getting it repaired. You'll be fine.

wolftree · Oct 29, 2013

Just tell everyone that an American spy drone collided with you as you were working ground.

Tony M · Oct 30, 2013

Thanks Guys for the replies.

Was mowing all day so didn't get to do much in the way of repairs. However, I did try to clean up the damage with sandpaper with a view to getting a bumper repair kit and putting a bit of filler on it to sand back to smooth when get some time.

What surprised me a bit is that the plastic material seems very powdery and tended to disintegrate as I sanded it - not really like the hard plastic I expected. It's whitish stuff under the green paint. Anyway, it's not under any stress, so I hope some plastic filler will stick, be easily sandable and stabilize things until I can paint it.

It's only a fairly small area and will probably not be noticed if I do a half-way reasonable job of matching the contours of the lip with the final sanding before spraying a few thin coats of JD green. Of course, if the filler doesn't stick, things could get messy.

Anyone have any definite info on the type of plastic used?