Posted: Fri Apr 30, 2010 2:53 pm Post subject: Hat Channels
OK, maybe I am late to the party on this one.
After I found out my source for NOS Fender Brace hat channels for the early style M38A1 fenders was depleted I began an intensive search for a new supplier. After being told by multiple venders that this hat channel is not available in reproduction or NOS anymore I was about to try fabricating new ones when I made a critical observation.
The original and reproduction (MD Juan is the source) right front fender hat channel for the Willys MB is virtually identical for both the right and left hat channels on the front fenders of the early M38A1... the ones that fasten into the chassis.
I measured a '45 MB and the early '53 M38A1 hat channels and the measurements match. None of the part numbers match or interchange in any manual I have for reference but the parts appear to be the same.
Good news for early M38A1 owners or am I way off?
If true, all those early style fenders can be saved for repair.
The MB manual shows
A2843 Brace, left
A2844 Brace, right
The M38 manual shows
A2843 Brace, left ORD# 7697493
A2844 Brace, right ORD# 7697494
The M38A1 manual shows:
680125 Brace front 2 ea MD10001-60406
684285 Brace front 2 ea MD60407-73456 ( I believe that this serial cutoff is what should have been shown for this part number but the manual failed to note it.
I ignored the other listed part numbers in the A1 manual that were simply more complete assemblies with weld nuts of the previous two part numbers.
I have two NOS M38 braces and I will try to find them and compare them to a M38A1 pair of fenders. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
Apparently MD Juan sells the same front fender hat channels for the MB, M38, CJ2A, CJ3A, and CJ3B. But not for the early M38A1.
Given the production numbers from Willys for these vehicles if they are actually the same hat channel design Willys must of had a number of sets of tooling to produce this part in the quantity needed for the assembly lines. This could account for the slight variations I have noticed in the parts I measured. The actual part dimensions were the same however.
The only area on the hat channels that is a real suspect is where the curve on the A1 and flat spot on the MB inner fenders touch or do not touch the hat channel. Given the complexity of this part design any variations in part to part might just be a normal percentage of error in production. The '45 MB and '53 A1 I measured are not a perfect match in regard to profile, otherwise they are the same. But, they appear too close to be a coincidence. Need a tooling engineer here for their opinion on 1950's part tolerances in sheet metal stamping.
Just a guess that with the radical change in design for the A1 Willys renumbered this part. They are slightly modified on the left one with weld nuts anyway. Also, since the right and left front fender hat channels are essentially mirrors of each other on the A1 while the earlier fender hat channels have different designs for each side a new part number might of made sense.
It looks like the best way to test this theory is buy the parts and try welding them in place. Hopefully, this will happen soon...
I believe you will find the different part numbers accommodated the battery tray on the right side which made a large rectangular depression back to where the brace installed. The part number change was not a common occurrence at Willys. Normally minor deviations and changes to parts occurred at Willys as changes to the basic part drawing but not the part number. When they changed a part number the change was normally more substantial than the other changes. I think you will find a serious difference in 3 dimensional profile or weld nut and hole placements between the two braces. As I mentioned above there was another significant change in the brace at MD60406 that was used thru MD73456. Then after MD73456 the brace was no longer used. My gut feeling is the switch from the early diagonal seem fender to the later vertical seam fender occurred at MD60406 and the modified brace was continued in use until MD73456 where it was dropped. I also think MD73456 was where the frame changed as well. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
I looked at the hat channels again and to simplify what we are talking about the conclusion I have come up with is that:
1) the MB right front fender hat channel is a different part and part number from the M38A1 front fender hat channels left and right. They are not exactly the same. They are not made with the same tooling to be correct. Being 8 years apart in production this is not a surprise.
2) However, while these may be different parts they do share the same basic dimensions, construction, function and installation.
3) Because the MD Juan MB right front fender hat channel is a 3rd and more universal design it may be essentially as close as someone will get in a reproduction part for the early M38A1 front fender hat channels. The left one needs 2 holes drilled and modified with the 2 weld-on tabs to make a near perfect replacement part, however.
I am going to order the MD Juan parts and test this part to see if it will fit. It may need a little hammer and dolly work or shrinking/stretcher work to fit properly but the parts look like they should fit near perfect without any work. And, just for the record the Willys parts are somewhat ill-fitted anyway. Once installed I suspect no one will know the difference from original parts.
I'll post some pictures that will better explain this if it works out.
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