Front bumper adjustment on a C4
08-05-2015, 12:38 PM
#21
Link is dead. Anyone have the PDF?
Bringing this back from the dead anyone have any documents or info etc that was talked about in this thread ? Did a bunper swap yesterday and the gap between the hood and bunper cover seems excessive . Thx!
Mikegillvt@hotmail.com
Mikegillvt@hotmail.com
Thanks to any responders.
Art
08-05-2015, 02:42 PM
#22
Race Director
Bringing this back from the dead anyone have any documents or info etc that was talked about in this thread ? Did a bunper swap yesterday and the gap between the hood and bunper cover seems excessive . Thx!
Mikegillvt@hotmail.com
Mikegillvt@hotmail.com
08-05-2015, 03:13 PM
#23
Mine is a 1993. Third owner so not sure if the bumper is original, but i think so. My good alignment looks good at the door gaps. My issues are the front gap between hood and bumper. Also the gap between hood and lower front quarter panel on driver side is not even. This is the gap in front of the wheel on the d/s.
Any help greatly appreciated.
Any help greatly appreciated.
08-05-2015, 04:17 PM
#24
Race Director
The gap between the hood and bumper cover is usually made by adding or subtracting shims in the area shown a few posts up. The 90 up bumpers also can be adjusted with the top bracket (its what the top of the bumper cover attaches to) Its generally used for evening the gap and height across the front. You will need to remove the bumper cover, or at least lift it to do this. The side gap is adjusted by manipulating the corner bracket that runs across the side of the bumper cover. This can be a pain as you have to balance adjusting the inner fender with adjusting...sometimes forming (bending the upper medal bracket) and moving the front innerpanel up-down-front to rear-sometimes shimming out. The bottom supports and the side brackets must be loose when adjusting the top, otherwise your gap adjustment will move when you tighten it down.
08-05-2015, 05:04 PM
#25
Okay...if I follow you, the cover has to be loosened up to access the corner bracket?
I have the FSM for the 93 year. I will look at it for some additional guidance. If you have any photos, of what I'm looking for, it would be greatly appreciated...
AR
I have the FSM for the 93 year. I will look at it for some additional guidance. If you have any photos, of what I'm looking for, it would be greatly appreciated...
AR
08-05-2015, 05:15 PM
#26
Race Director
To adjust the side you need to just loosen that side, including the 10mm inner fender mounting bolts, and all of the bolts/screws that mount the top side bracket. Be aware though that this can change the gap and height on that top corner, so you may need to loosen the top to correct that. Sometimes it takes a lot of manipulation, because the bumper cover or inner fender gets a "set " to its shape over the years, or brackets have gotten bent over the years.
03-17-2016, 02:20 PM
#27
1st Gear
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Info
There are two horizontal brackets that have "some" adjustment to equalize the spacing between the hood and the front cover. I have a Power Point file and a Word document that I can send you that shows the brackets, adjusting screws and some words describing how it done. I did this for another forum member a few years ago as he was interested in how I made the adjustment on my 89.
I will need your email address if you are interested in the files. The bad news is that you must remove the front bumper cover to make the adjustment.
I will need your email address if you are interested in the files. The bad news is that you must remove the front bumper cover to make the adjustment.
05-16-2016, 04:19 PM
#28
The problem that I have (on my 1996 Collector Edition) is that the nose is skewed to one side. Hood alignment is good. Spacing between hood and nose is good. Height is good. I just need to scoot the nose to the left about 1/4". Any info much appreciated!
05-17-2016, 06:51 AM
#30
Le Mans Master
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Take it from me, it is very important to tighten all the bolts before hitting any pot-holes! (Ask me how I know!
)
The bumper cover DOES NOT need to be removed. And, know there are two bolts on each end of the front bumper that go into adjustment slots on the frame support.
Shims are designed with slots such that the shim is first aligned (hung in place) on the top bolt and once the top is in place, the shim is swiveled (rotated) so as to align with the bottom bolt, ready to be secured. (If need be, I can trace one and hood shims too and mail the pattern(s) to you, should you need to fabricate some any.)
)The bumper cover DOES NOT need to be removed. And, know there are two bolts on each end of the front bumper that go into adjustment slots on the frame support.
Shims are designed with slots such that the shim is first aligned (hung in place) on the top bolt and once the top is in place, the shim is swiveled (rotated) so as to align with the bottom bolt, ready to be secured. (If need be, I can trace one and hood shims too and mail the pattern(s) to you, should you need to fabricate some any.)
Last edited by Paul Workman; 05-17-2016 at 06:54 AM.
05-17-2016, 10:44 AM
#31
I found those bolts (all 4 of them). They both have about 3/8" of shims behind them, and the front to rear (hood edge) alignment is good. I see they are slotted for vertical adjustment. However, I see no means of HORIZONTAL adjustment, and that is what I need. Am I missing something?
05-17-2016, 10:49 AM
#32
Take it from me, it is very important to tighten all the bolts before hitting any pot-holes! (Ask me how I know!)
The bumper cover DOES NOT need to be removed. And, know there are two bolts on each end of the front bumper that go into adjustment slots on the frame support.
Shims are designed with slots such that the shim is first aligned (hung in place) on the top bolt and once the top is in place, the shim is swiveled (rotated) so as to align with the bottom bolt, ready to be secured. (If need be, I can trace one and hood shims too and mail the pattern(s) to you, should you need to fabricate some any.)
)The bumper cover DOES NOT need to be removed. And, know there are two bolts on each end of the front bumper that go into adjustment slots on the frame support.
Shims are designed with slots such that the shim is first aligned (hung in place) on the top bolt and once the top is in place, the shim is swiveled (rotated) so as to align with the bottom bolt, ready to be secured. (If need be, I can trace one and hood shims too and mail the pattern(s) to you, should you need to fabricate some any.)
05-17-2016, 01:10 PM
#33
Safety Car
I found those bolts (all 4 of them). They both have about 3/8" of shims behind them, and the front to rear (hood edge) alignment is good. I see they are slotted for vertical adjustment. However, I see no means of HORIZONTAL adjustment, and that is what I need. Am I missing something?
05-17-2016, 01:52 PM
#34
The shims are for forward/rearward (gap) adjustment. The slots allow up/down and left/right adjustments. You can't see the left/right slots, because they are in the bumper bracket. You can only see the up/down slots in the frame bracket. You don't need to remove the nuts. Just loosen them a little, to allow movement. If you loosen them too much, the bumper will drop to the bottom of the slots! You may need to loosen the bolts for the skid pads on the bottom of the bumper, but for left/right adjustment, I doubt it.
05-17-2016, 02:33 PM
#35
Le Mans Master
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The main adjustments are the 4 bolts, two on each side, located at the end of the frame "horns" that are holding the bumper itself to the frame. There is about 3/4" of total vertical adjustment, and shims are used for adjusting the gap between the hood and the bumper itself.
The bumper cover is secured around the periphery of the cover, which may or may not need to be loosened just enough to allow the cover to shift, depending where shifting takes place.* And, there are two fender supports, one on either side that secure the upper rear corner of the fender; two bolts on each securing the fender (which will likely need to be loosened, especially if shims are to be inserted between the frame and the bumper itself).
It may take you a full day to get everything aligned the way you want it. Whereas a good body man might get it done in an hour or two. Experience makes a huge difference when it comes to body work. But, take your time and you'll come out fine.
I mention all of this so you are aware of what can or might need to be adjusted, not that you'll have to do much more than loosening the bumper and perhaps some periphery cover screws, and add a shim or two.
As mentioned, the key reference points are the hood to door alignment/gaps are to be "perfect" when latched. then the bumper and bumper cover are oriented to agree with the front edge of the hood. But, before cinching everything tight, check the "belt line" for straightness, using a string or long straight edge and view alignment of the belt on both sides. (Chances are you will need some shims under the hood hinges too and the bumper adjusted so that the belt line straight across the entire car.
That's a lot of adjustments to tighten. At the factory in Bowling Green the cars are driven over a set of "speed bumps" and the panel alignments are checked again afterward. Be sure to tighten everything before calling it good: trust me! Otherwise stuff will shift!
05-17-2016, 02:45 PM
#36
Loosen, but not disconnected... Virtually every panel has some positioning slots to allow alignment. And, often "everything affects everything". But, for a small tweak (like yours?) you may get away with an easy fix.
The main adjustments are the 4 bolts, two on each side, located at the end of the frame "horns" that are holding the bumper itself to the frame. There is about 3/4" of total vertical adjustment, and shims are used for adjusting the gap between the hood and the bumper itself.
The bumper cover is secured around the periphery of the cover, which may or may not need to be loosened just enough to allow the cover to shift, depending where shifting takes place.* And, there are two fender supports, one on either side that secure the upper rear corner of the fender; two bolts on each securing the fender (which will likely need to be loosened, especially if shims are to be inserted between the frame and the bumper itself).
It may take you a full day to get everything aligned the way you want it. Whereas a good body man might get it done in an hour or two. Experience makes a huge difference when it comes to body work. But, take your time and you'll come out fine.
I mention all of this so you are aware of what can or might need to be adjusted, not that you'll have to do much more than loosening the bumper and perhaps some periphery cover screws, and add a shim or two.
As mentioned, the key reference points are the hood to door alignment/gaps are to be "perfect" when latched. then the bumper and bumper cover are oriented to agree with the front edge of the hood. But, before cinching everything tight, check the "belt line" for straightness, using a string or long straight edge and view alignment of the belt on both sides. (Chances are you will need some shims under the hood hinges too and the bumper adjusted so that the belt line straight across the entire car.
That's a lot of adjustments to tighten. At the factory in Bowling Green the cars are driven over a set of "speed bumps" and the panel alignments are checked again afterward. Be sure to tighten everything before calling it good: trust me! Otherwise stuff will shift!
The main adjustments are the 4 bolts, two on each side, located at the end of the frame "horns" that are holding the bumper itself to the frame. There is about 3/4" of total vertical adjustment, and shims are used for adjusting the gap between the hood and the bumper itself.
The bumper cover is secured around the periphery of the cover, which may or may not need to be loosened just enough to allow the cover to shift, depending where shifting takes place.* And, there are two fender supports, one on either side that secure the upper rear corner of the fender; two bolts on each securing the fender (which will likely need to be loosened, especially if shims are to be inserted between the frame and the bumper itself).
It may take you a full day to get everything aligned the way you want it. Whereas a good body man might get it done in an hour or two. Experience makes a huge difference when it comes to body work. But, take your time and you'll come out fine.
I mention all of this so you are aware of what can or might need to be adjusted, not that you'll have to do much more than loosening the bumper and perhaps some periphery cover screws, and add a shim or two.
As mentioned, the key reference points are the hood to door alignment/gaps are to be "perfect" when latched. then the bumper and bumper cover are oriented to agree with the front edge of the hood. But, before cinching everything tight, check the "belt line" for straightness, using a string or long straight edge and view alignment of the belt on both sides. (Chances are you will need some shims under the hood hinges too and the bumper adjusted so that the belt line straight across the entire car.
That's a lot of adjustments to tighten. At the factory in Bowling Green the cars are driven over a set of "speed bumps" and the panel alignments are checked again afterward. Be sure to tighten everything before calling it good: trust me! Otherwise stuff will shift!
04-26-2020, 01:13 AM
#37
Navigator
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I had to remove the front bumper to repair the parking lights and also to adjust the front bumper. I had a lot of trouble getting it off. is there a chance that some bracket is bent.
I am unable to put it back on. This is why I think something is bent. Has anyone had this problem before?
I am unable to put it back on. This is why I think something is bent. Has anyone had this problem before?
