Author Topic: Help with aligning fenders to doors  (Read 10076 times)

Offline firefighter

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Help with aligning fenders to doors
« on: January 16, 2012, 10:39:44 AM »
Hi guys,

I'm here to tap on your knowledge once again.

If any of you have ever installed and aligned fenders, I'd be interested to know the sequence in which you do it, or a few tips if possible. I temporarily installed the fenders to check for tire fitment but they seem like like they are gonna need some coaxing.
I haven't reinstalled the painted doors on my new cab yet but I feel I have them adjusted pretty good as far as gaps go.
I'm going to put the doors back on within the next couple days and want to do a total fit check of both fenders to see if I need to enlarge any mounting holes before I paint them.

Here is the question for anyone who has ever installed fenders successfully.
Do I install all the mounting bolts first and then try and start flexing and shimming to get things to line up?
Or do I support (but not bolt) the front of the fender while I get the rear of the fender aligned with the door?
I was wondering if it would be beneficial if you didn't bolt the front of the fender in place so that you could raise or lower it to aid in fitting the rear of the fender.
Shimming up/down and in/out is seems straight forward, but aligning the gaps has me concerned.

Thanks for any tips you could offer.

Offline Doms86Shortbed

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Re: Help with aligning fenders to doors
« Reply #1 on: January 16, 2012, 11:00:45 PM »
What worked best for me since i didn't have any helping hands was to bolt the fenders to the rad support in the front first (keeping them loose of course). then shimming and coaxing the rear the align with the door. once the door/fender alignment was good i cranked down on the bolt that holds the fender to the cowl, and the one below that holds it to the cab. then i went back up front and aligned the fender and hood. mistake me if im wrong but i believe the proper gap space should be 3/8".

Offline Irish_Alley

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Re: Help with aligning fenders to doors
« Reply #2 on: January 17, 2012, 05:24:59 AM »
you want to put the doors on first get the aligned with the rear of the cab then work on the fenders. it will suck getting the fenders lined with the door just have the doors not be lined up with the cab
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Offline 69byrd

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Re: Help with aligning fenders to doors
« Reply #3 on: January 17, 2012, 07:17:08 PM »
It also doesn't hurt to enlarge the holes.
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Offline HAULIN IT

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Re: Help with aligning fenders to doors
« Reply #4 on: January 17, 2012, 08:33:44 PM »
Unless you have a real need to get the painting done, I would finish the wiring, dash, carpet, seat & belts, ect. inside the cab before installing the doors. They just get in the way while working inside.
Once that's done, put the doors on & load them. Now your ready for the front clip. Put the rad. support on (with no shims) & just snug the bushing bolts. You want the cab bushings tightened.
A couple things that concern me is that without the doors on, your identifying problems...What are you seeing? Did you test fit the fenders to the doors prior to painting the doors?
On to your questions. Really only Two bolts count when fitting the fenders, the rest just hold it still in various places. The bolt on top of the cowl is the most important & the first one to deal with. Shim it up until you have the bodyline correct with the door & tighten it where it is lined up in/out with the door. Next, put the top front bolt into the rad. support. Do this on both sides.
Hopefully, your gap will be slightly wide @ the bottom & will close up when you tighten the rad.support bushings. If your gap is tight @ the bottom...you need to shim the rad. support up. If you have a BIG gap @ the bottom...you'll need to shim under the front cab bushing. Once you have this done, it's just a matter of putting in the bottom bolt & the one in the upper jamb (shimming as needed to keep the fender where you need it).
It wouldn't hurt to check a "X" from the top bolt @ the cowl to the hood bumpers to locate center.
This should keep you busy for a little while. Lorne

Offline firefighter

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Re: Help with aligning fenders to doors
« Reply #5 on: January 17, 2012, 09:43:51 PM »
Excellent replies for sure!!

I actually got the drivers side door pinned back in place this evening and then aligned the fender to it.
I did not have a helping hand so I had a strap supporting the front of the fender while I began aligning the rear of the fender.
I did just as Haulin It said and put the top fender bolt in first and set the fender to door gap at the top. I had to lower the front of the fender to close the gap at the bottom of the fender/door. I then tightened the rear bottom fender bolt at the door.
The problem now was that the front of the fender was about 1" low and I really had to muscle it back up to get the radiator support bolts to go in. Now this is an aftermarket door and not an original GM door.
So Mr. Haulin It,  you're thinking I may need to raise the front of the cab just a touch to maybe help this a bit?

Hopefully tomorrow night I'll do the same thing to the passenger side (this one is a GM door) and see how it fits. If I run into the same problem, I will shim the front of the cab a bit. Just not so much that it begins to look off with the box.
Hey, I can see how all this can work together now. These little tricks of the trade are exactly what I (and others who will do this) was looking for.
You guys are awesome!!
Thanks !!

Offline Sartobuilt

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Re: Help with aligning fenders to doors
« Reply #6 on: January 17, 2012, 10:11:25 PM »
X2 on what haulin it said. Plus most of the trucks I've seen have a shim at the front cab support. Bolt the radiator support loose then the top bolt by the door, I will then jack up the front of the cab to line up the lower fender and shim and tighten the middle and lower bolts then let the cab down. That will put the proper load on the radiator support. In your situation since you already have the fender lined up to the door, jack up the front of the cab to line up the fender with the radiator support. Definitely do a X measurement for the hood, it will make it allot easier to install the hood. I also leave the cab mounts loose you might have to move it around to square up the front clip.

Offline firefighter

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Re: Help with aligning fenders to doors
« Reply #7 on: January 18, 2012, 10:06:33 AM »
Thanks again for the replies. They really make sense and will make final lining up a bit better.
I would have never thought a person could shim the front of the cab to help with fender alignment. That info. in itself is very helpful.
I did a bit of measuring this morning before work. If you shim under the front cab bolts, by the time you get to the front of the fender, that raising distance will be amplified.
For example, it is  42" from the rear cab bolt to the front cab bolt. Then from the rear cab bolt to where the fender bolts to the radiator support is about 8'. From my calculations, about 1/8" of shim on the front cab bolt will increase to about 3/8" to 1/2" by the time you get all the way to the radiator support. This is gonna help me out a whole bunch!!
My fear is that I'm thinking the other fender will have to be adjusted just the opposite, just by looking at it.
I'll know more tonight.
The real question is (if the other side is opposite), would a person ever shim under just one side of the cab, and under the opposite side of the radiator support? Or would that be making things way off?

Thanks guys. You're a wonderful source of information of us "do it yourself" guys.

Offline HAULIN IT

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Re: Help with aligning fenders to doors
« Reply #8 on: January 19, 2012, 09:45:35 PM »
My fear is that I'm thinking the other fender will have to be adjusted just the opposite, just by looking at it.
I'll know more tonight.
The real question is (if the other side is opposite), would a person ever shim under just one side of the cab, and under the opposite side of the radiator support? Or would that be making things way off?
This shouldn't be a problem. Remember these trucks have been around the block a few times. What your shimming, bending & slotting for is possibly a combination of many things: Bent frame/mounting brackets, poor quality control when the truck was made, poorly made a/m parts & various other reasons. Just because you put an 1/8" shim under the cab mount, doesn't necessarily make the cab sit crooked...you most likely have just put it where it should have been. Nothing wrong with a shim under the Left front cab mount & under the Right side of the rad. support or any other combination. Lorne

Offline Sartobuilt

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Re: Help with aligning fenders to doors
« Reply #9 on: January 19, 2012, 09:48:40 PM »
Shim where ever it needs it. These were never perfect. If you have it on a level floor, which i hope you do, measure all the mount heights that will give you an idea of where to start. The first thing I do when I set a cab on a frame is to see if it rocks. Start with a shim and go from there.

It takes some time and patience.