Re: N/A 74mm Throttle Body Upgrade Guide
I would not recommend doing all this work without replacing the O-ring, any small air leaks would probably not make much difference but why risk it. They never fit the same most times. The O-ring used is very soft and appears to have been 3/32" by 3 3/16" outside diameter. The regular O-ring most easily purchased is harder and would not squash like the OEM one. The trouble is these normal type O-rings may not stand the constant heat like the OEM ones. If a normal material (Nitrile) O-ring was used a 3/32 by 3" inside diameter may work. I'll think about that problem, but probably buy the OEM part, part # 05102933AA, this is $17.35 list and $14.60 net in Canada. Not in stock at my Chrysler dealer but came in after just two days.
Why spend $100 on a TB and save $10 on a O-ring or if your local mechanic did it you would think he did a half assed job.
The method of removing the throttle body originally spelled out in the PDF is asking for breakage of the molded clips. It is not the recomended method at all. I would unlock and remove the ring that locks around the MAF and not bend the tabs that are a part of the clip, these are plastic parts and we would not want to break them. These tabs are not designed to bend, they are locks.
I warmed up the breather hose attached at the bottom driver side of the elbow with a heat gun a little and it came off easily.
This photo shows the method to release the lock ring.
This photo shows the ring unlocked. The ring can then be removed from the MAF.
After removing or at least loosening the lock ring, pushing these two clips in the directions indicated allows the MAF unit to come off in one piece and that is better than separating them. Actually pushing down on the bottom one allowed the unit to swing out and away from the throttle body.
This view shows where the clips snap onto the throttle body.
A view of the 74 mm Throttle Body, Mercedes #A1131410125 attached to the OEM MAF unit. when reassembling the MAF to the throttle body make sure it is square or it will be hard to attach the clamp shown in the top picture.
New O-ring, #05102933AA, Mercedes #3059970345
The larger MAF next to the OEM MAF showing the extra 3/8" (approx) larger bore. The sensor in the OEM unit was reinstalled into the larger unit. The Larger unit shows the sensor loosened and askew. The screws holding the sensor in place are the five point (not the normal six point) Torx TS style. These are the tamper resistant style and baffled me until Beaner said I could use a small flat head screwdriver on them. I had a tamper resistant flat head bit and it fit like a glove.
Last edited by onehundred80; Apr 13, 2011 at 06:46 PM.