Question on fender fitment

[kwah]

I’m in the process of a ST backdate. 1982 SC. I’ve installed the front fenders and hood and have a couple questions.

I started by removing the oem fenders and removed the old putty tape. I cleaned the mating surfaces. I found the rail that the fender bolts to along the hood line had some filler. I filed this off to bare metal, sanded and primed. Now when I snug gown the fender flush to the body it is pulled too far in causing the side of the hood rub eliminating the normal gap.

The fender is too tight and contacts the hood only on the drivers side approximately midway up the hood.

I’ve taken two strips of putty tape and put them together to see if that would be sufficient for a spacer. It’s not, I think I would need to double it up as in 4 strips, 1/4 inch or so.

My question, has anyone experienced this before? Should I reapply some filler to gain more thickness on the rail to space the fender out enough?

[30westrob]

Use a block of hardwood and a large hammer on the inner fender rail. Use a straight edge or other method to judge movement. These cars were hand built and their are old factory production photos showing this method for proper fitting. Sounds primitive but this is how it was done. Rob

[dhamilto]

I have tried it, but I am still not sure that adjusting the inner wing mounting strip method (instead of the fender itself) is the best way forward, because it has a noticeable effect on the position of the fender at the door end (similar problem with filler) but might be OK for adding the small additional gap that you need. That said, any adjustment here is quite reversible, and if its not painted yet, why not try it.... (much easier than adding filler I think).

I have tried the hammer method in the past but later found what I think is a more controllable method - I place about a half inch thick spacer under the seal lip and use a regular flat welding clamp to grip tight over the inner fender joining strip and spacer. I move up the length of the fender to lever in a slight tilt until I am happy with the gap. Be careful, because the (inner) fender strip bends easily along the (single skin) front section, and then needs a bit of muscle along the (double-skin) top half. I do this by eye (you can see the slightest tilt all along the strip), but can also fashion a card template to capture the original angle (keep a spare one) and then shave off 1.25 degrees for every 1mm of fender gap you want to add and use this to get your new tilt angle.

A couple of other little tricks I learned - the final gap will only be found when the fenders are bolted up tight, but you can see if this inner wing gap is even with only the fender joining strip bolts in place, and a few turns loose (all the same). Look carefully along the interface between the fender and inner fender to check that the fender meets the inner fender all the way along, and add/mark pieces of masking tape where any a adjustments need to be made to the tilt angle of the inner fender strip.

At the moment (next week could be different ), I prefer to adjust the inner fender joining strip over trying to adjust the fender itself - I found it really easy to mess up the mounting strips on my (old rusty) fenders when trying to adjust based on the 'Porsche 911 fender gap detail' diagram, so now I dont mess with the fender (gap adjusting lip) at all.

I wonder how the factory did this originally, and what tools they used - maybe a long wedge between the hood and fender....?

Best of luck - please feed back what eventually worked best for you...

[mo-mon]

Try posting your issue on the Paint & Bodywork Forum. Maybe you will get more tips over there.

[kwah]

Originally Posted by mo-mon

Try posting your issue on the Paint & Bodywork Forum. Maybe you will get more tips over there.

Thanks, before I posted here I considered that but looking at the traffic over there or lack of I thought more would see it here.


The 2 post above have really helped out. I will post a follow up feedback of what worked for me.

Thanks.

[kwah]

@ Rob and dhamilto, Thank you. Helped out a lot.

[keith28]

The previous collision damage needs to be addressed properly.Ideally the car should be mounted on a chassis alignment jig preferably a Cellette to check for correct position of the suspension mounting points on the underside.
Then measurements should be made using a Tram gauge to determine if the front inner fenders and front latch panel are positioned in proper factory tolerances with respect to the upper most extremities which are the fender mounting flanges and front hood latch panel.
Body filler on those areas to make up for out of tolerances is not acceptable.Sometimes a sideways pull is required which because the front latch panel is attached to both sides will move both sides bringing them both into the correct position so that the hood gaps to fenders becomes correct and parallel.This will also help allow correct gaps from the fenders to the front edges of the doors.
As a preliminary check at least do some X measurements to cross check to inner fenders from back at the hood hinge corners diagonally to the front opposite corners of the front hood latch panel.

[kwah]

Originally Posted by keith28

The previous collision damage needs to be addressed properly.Ideally the car should be mounted on a chassis alignment jig preferably a Cellette to check for correct position of the suspension mounting points on the underside.
Then measurements should be made using a Tram gauge to determine if the front inner fenders and front latch panel are positioned in proper factory tolerances with respect to the upper most extremities which are the fender mounting flanges and front hood latch panel.
Body filler on those areas to make up for out of tolerances is not acceptable.Sometimes a sideways pull is required which because the front latch panel is attached to both sides will move both sides bringing them both into the correct position so that the hood gaps to fenders becomes correct and parallel.This will also help allow correct gaps from the fenders to the front edges of the doors.
As a preliminary check at least do some X measurements to cross check to inner fenders from back at the hood hinge corners diagonally to the front opposite corners of the front hood latch panel.

Keith, thanks, no accident damage. The filler I mentioned was more of a skim coat type of thickness to smooth the rail. Measurements check out good. Was able to bring it within good gaps with some hammer and dolly work. I was naive enough to think that backdate fenders would bolt right on without any massaging.