Date registered: Dec 2004
Vehicle: w124 400E x R129 w210
Mentioned: 1 Post(s)
Quoted: 20 Post(s)
You're focused on the wrong side of the wheel...flip it over. The problem is inside.
As I said..it isn't that easy.
This 93 wheel out of a 400E has the same mounting hub, with 2 holes, as the 94 and up so no need to drill anything here and that isn't the problem...it's more involved then that.
The horn ring mount in the center of the 93 wheel, the spring loaded part that moves when you push the airbag to activate the horn, has 2 issues that stop it from being as easy as just swapping parts...like the hub horn ring......
1)... the 4 mounting points (actually 5..there is one right at the bottom) molded into the 93 wheel are at a different height from the bottom (or top) than on the 94 and later wheels. So you can't just swap the horn ring assembly along with with the concentric contact rings into the new wheel...the hub will not fit.
2)... even if you did ONLY swap the contact rings (squibb) into the new wheel and leave that horn ring hub in place....it still won't work because the grounding is different on the two horn rings! And when you try and use the horn by changing only the squibb into the later wheel, it keeps blowing fuses. DEAD SHORT.
Each of the four electrical contacts (top / bottom) on the early horn ring assembly from the 93 car (the one with the concentric circle contacts or squbb) are insulated, individually, from the top and bottom plate. Therefore, they are wired individually with a wire running to each of the four insulated contacts, around the bottom, to the ground wire coming from the contact ring!
The same 4 contacts on the later (94 up) horn ring are not wired separately at all. They are just an UN-insulated upper and lower copper contact riveted to the upper and lower horn contact plates.
With this set up you just plug the ground wire coming through the center hub onto the contact "ear" on the lower plate, left or center. This one connection grounds the whole lower ring on the 94+ as opposed to the 93 wheel. On it each contact is grounded individually and insulated from the bottom plate itself.
So, to swap a wheel from a later (94+) car WITHOUT the concentric "squibb" you must swap out the squibb AND the center horn ring because it has the individually insulated contacts that the "squibb" wiring requires.
BUT, if you are to swap the hub and squibb (and you must) then the new wheel must have the same molded mounting point positions in the wheel, for the hub, as the 93...or the hub won't fit, it'll sit to high.
Now, having said all that...it is possible that the mounting position for the hub is only an issue with the 92/93 400 / 500E wheels.
Can't imagine why but maybe.
Maybe the 300E wheels with the contact ring squibb for 92/93 have the same molded mounting points in the wheel as the newer 94+ wheel. In that case there isn't a problem because you just swap over everything..the squibb and the correct mated hub with the correct insulated grounding wire.
Solution ? ...for this set-up (93 400E wheel with contact rings swap to 94 wheel without )....well, there isn't one!!....unless somebody knows how to deal with the correct grounding of the uninsulated horn ring to the contact ring squibb so it doesn't generate a dead short when you engage the horn....OR...fit a later wheel that has the same hub mounting position so you can move over everything.....squibb and insulated contact hub.
Surprised this has never been discussed before......nobody seems to mention the separate insulated ground contacts on the early wheel...nor to mention that there are two different horn hub mounting platform heights on different wheels....weird.