308GT4 rubber bumper insert

My question relates to EU car - no idea if the same is for USA cars.

My rear bumper chrome needs rechroming. My car is 79 though built in late 78. I doubt bumper chrome and rubber have ever been separated since it was built.

Anyway today - having changed the fluids before winter, I set about the other winter jobs. First up - remove the rear bumper. Not as easy as thought. I had to put a suitably sized socket into the tube that supports the bumper, and give it a good few whacks with a hammer to get it to move

Anyway - eventually got it off..

Then started trying to undo the bolts that secure the chrome to the rubber with minimum pressure. A grate then the bolt rotates freely with a grating noise but doesn't move out.

Quickly ascertain that bolt goes into a lug moulded into the rubber but that the whole thing is so corroded that the slightest turn with a socket shreds the rotten metal in the lug.

So far have managed to remove 5 of the 6 bolt/lug assemblies. One still being difficult, which I'll sort out with a different tool tomorrow. There are then two embedded bolts on each of the reversing lights which I may be able to free up, though the first one I tried just seems to turn the whole assembly.

So to come to the point. The rubber is still fine. I now just need to anchor new studs into the rubber so I can bolt to the chrome. There are holes in the rubber where I can locate the new studs (bolts). Has anyone done this and have any recommendation on suitable adhesives/fillers to secure the studs?

 

I'll post some pics tomorrow. I am using Metal polishing in Oxfordshire -- AK MOTO who are half an hour drive from me so very handy.

 

Thanks Gav. there seem to be various different versions so any more info would be great.

 

Thanks Gavin, I guess that is Flexane 6. I will order some.

Meanwhile I will post some pix of my project.

 

Here are pics. Commentary tomorrow. Have to go to bed now/.
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The guy who rents the barn opposite where my car lives, and who looks after a number of top class period racing cars for a number of high profile owners, recommended these chromers in Coventry to me. He has used them for years and says they do a top quality job at a reasonable price. He does know what he's talking about as all his clients demand the best

Chrome plating of classic car and bike parts. Full restoration including vintage and custom. Specialists in Jaguar, Rolls Royce, Bently, Triumph, MG, Aston Martin.

I think however I will stick with my first choice as they seem to have a good reputation and being only 30 mins drive away it's much easier to deliver and collect.

Meanwhile I am still working to get the last bolts undone to release the rubber from the chrome. These are the 4 small studs, 1 on each side of the reversing light, through a small bracket. At the moment they just turn the whole bolt/stud.As I am not sure how they attach underneath (I've taken the reversing light lenses off but that doesn't reveal anything) I am a bit loathe to cut them till I understand how it is put together. So I have been soaking them with Wurth Rost Off Ice which QV tell me is the best rust penetrator around and maybe I will be able to unscrew them - but I'm not very confident. Maybe will just have to cut them and work out how to fix it thereafter.

The Dino parts rear bumper rubber looks interesting. But it says it is for chassis numbers up to 12162. Mine is 14302. I don't really understand that because a) I didn't think there was any change to the rear bumper from series1 to series 11, and b) 12162 seem to me to be a series 11. I will enquire with them

Superformance also offer a fibreglass insert, but I don't want that. It looks shiny and horrible. I am sure I can rescue my current rubber, which I notice now I have the bumper off, has some cuts in it, so I need to investigate repairing those. Maybe Flexane.

Here's a repost of the pic that show the small studs around the back of the reversing light. The nut on top of the big washer is the one in question.
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Have now cleaned up the reversing light lenses using some of my wife's nail varnish remover pads. They have gone from dark yellow to clear. Brilliant!

 

Still trying to undo the 4 remaining nuts on the studs that hold the reversing lamps. Superformance are going to send me a photo of the mounting on the rear of the replacement reversing lamps they sell so that I can work out whether I can recover my original ones if I have to cut the studs. If the worst comes to worst I can replace them but they aren't exactly cheap.

I going to wait till I've got the rubber and chrome separated before ordering the Flexan as once again it is not cheap.

Meanwhile (though not exactly on topic) I've moved onto the rear lamp clusters. Luckily once loosened a turn the nuts were only finger tight, just as well as there is very little space to get a spanner to them. I knew my lights were a bit dim, even after I fiitted more modern bulbs, and I hoped it was just dirty lenses. But ouch! As you will see from the pics the rust worms have been at it. The chrome was like wrinkled aluminium foil completely detached from the reflector boil and fell apart at the first touch. Luckily there is plenty of metal still there and after a bit of polishing those too will be going to the chromer.

I'll take the other cluster off tomorrow and hope I find nothing worse.

Onwards and upwards
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Hi Gav

I do have a Dremmel. Not sure what a small car bite burr is. Can you point me to one?

 

Ahh!.

Predictive texting. Carbide burr!

I will check what I have and buy more if needed. Good idea

 

Thanks Gav,

I ordered them then discovered I already had one suitable bit and this afternoon successfully cut the nuts off and have separated the rubber insert from the chrome bumper. Taking the bumper to be rechromed tomorrow. The anchorage points in the the rubber insert are in a bit of a mess, quite a lot of splitting which predates any damage I might have done removing the bolts, and now I have been able to se it properly I will order some Flexane and set about repairing and embedding some new studs.

Meanwhile finally managed to get the second rear light cluster off. Sod's law there had to be just one nut that was rusted on and of course it was the most inaccessible one. Yesterday I cleaned off the thread with a Dremel wire brush and squirted is with Rost Off Ice. After much faffing around on it again today ( the whole stud just rotated with the nut) I gently tapped on the other studs to loosen the assembly and lo and behold the whole assembly came of leaving the recalcitrant stud still in place in the chrome surround. Strangely the chrome on these reflectors is in perfect condition.


Just to complete work on the rear of the car, I have also taken off the number plate lights. One of the lenses came off in 3 pieces so a bit of gluing is needed. The lenses were so filthy I am surprised any light came through them at all!g

 

There were some fibreglass ones. Supposedly due to Ferrari unable to pay suppliers. But who knows.

 

Went to the trimmers to pick up my refurbed seats. Look beautiful

Then refitted them. Not the easiest of tasks for a big bloke like me, but eventually done.

Then I turgned my attention to the rear rubber bumper insert which if you recall I finally managed to separate from the chrome bit a couple of weeks ago. As far as I can make out the rubber is formed round a metal base which includes threaded bosses for nuts to secure through the chrome outer section. As I reported before 3 of the five bosses were just a mass of rotten rusted metal. Anyway, today I used a burr tool in the dremel to grind out the remaining rotten stuff preparatory to embedding some bolts using some rubber putty called Flexane. Don’t know if you have come across it but it has been highly recommended to me. Not cheap. Anyway I know have a 500ml can. (it’s a two part compound).

I need to do some trials. As you can see from the pic there is a lot of splitting of the rubber around the anchor points, presumably forced by rotting metal inside, and I am wary about how much to cut away and replace as the whole rubber insert is pretty much irreplaceable and I have to proceed with caution. Also removed more of the surrounds of the rear light clusters for cleaning.

Now need to go to the local fasteners specialists (they are amazing - they have everything and more) to get new and clean nuts bolts for reassembly.

Francis
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