Pagoda SL Group
W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: mrfatboy on September 30, 2017, 18:34:11
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There is a grounding strap that is connected the engine block right behind the power steering reservoir. Where on the body (driver side inner fender) is it supposed to be connected to? It either has to be where the negative battery cable is connected to the body or the forward coil bracket bolt. Both spots have quarter sized non painted areas for grounding.
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On my '71 280sl, this ground strap coming from the block next to Power Steering Rez connects to the coil bracket to body bolt.
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It connects to the radiator on my 250SL lower left side bolt. I would love to get the P/N for this part, as the A116-------- cable is attached from the firewall to the transmission.
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JP,
the parts list shows p/n 110 540 01 31.
On my 280SL the cable is connected to the front coil bracket bolt just like Kampala's. But it has a different cable shoe on the engine end than the one shown in the parts list; it is a flat U-shaped metal piece that is attached 90 degree to the long cable axis. See photo.
Biggest discrepancy, however, is that the parts list has the cable attached to the cross (transverse) member and not the side (longitudinal) member.
{As explained in my later post, cable #16 in the picture goes from the firewall to the engine/transmission as JPMOSE wrote and is NOT the one on the block behind the power steering pump}
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Belowe is the EPC list with the latest numbers. As Alfred says - it says "to cross member". But the nuts and washers are sayong something else...
Added after Alfred's subsequent post: these are part numbers for engine/transmission/firewall ground strap, not for power steering reservoir/radiator strap.
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Thanks to both of you!! The A116 cable is the exact one that goes on the firewall to transmission. Someone told me the longer one from the radiator to P/S Reservoir is NLA. I'm determined to find one!!! :)
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I am terrified with my spelling...
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Sorry guys, I goofed! :(
Our parts guru Dave Gallon pointed out to me that part #16 is NOT the grounding wire from the block but it is the one that JPMOSE identified as the cable going from the firewall to the engine/transmission. The original p/n of that one was indeed:
110 540 01 31 replaced by
109 540 01 31 replaced by
116 540 02 31 or 116 540 05 31.
So what about the one on the block behind the power steering pump?
He pointed me to page 82-20 in the 1968 BBB which identifies this grounding strip as p/n 111 540 00 41. See attachment.
It is part of the "Interference Suppressor" kit when a radio needed to be installed. It is indeed routed from the block to the "upper lefthand oil cooler fastening bolt".
Unfortunately for JP this p/n is also NLA and the only solution is to fabricate one or find one at a junk yard. Apparently the cable was also installed in several other models from that time period. See text enclosed in red.
Also note the remarks about the grounding strap for the hood (in blue).
Dave Gallon thinks that the strip was necessary to bring the oil cooler/radiator to the same electric potential as the engine to prevent radio interference. Attaching it to the side member does no good. But he mentioned that this was frequently done by owners and mechanics who did not know because the strap interferes with easy removal of the battery.
Now, who is going to change the wire on their 280SLs? ;)
{I corrected my initial post to prevent any future misunderstanding}
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Great detective work and perfect timing. My new battery and tray are going in today. Perfect time to change it😀
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I have modified my post as well.
Yes, I am going to install this strip as I am struggling with noise on the radio.
As for the hood - we talked about it a lot and the only model of the car without a strip to bonnet was W113, where we have the Bronze Spring Thing.
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Thanks for this information!! Mine is in good shape...it's the black plastic sleeve that's cracked in places, but all this can be duplicated.
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It my 280SL, if this strap is disconnected the engine will not run.
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Which strap, the one from the firewall to the engine/transmission, or the one from the block to the radiator??
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This is the part number I used for the grounding strap radiator to engine (steering fluid tank): 115 540 02 41. It is an appropriate length, insulated in a sleeve, two eye-shape connectors. The only issue is both connectors are 8mm, while what is needed is one 8mm and one 6mm. I just installed it as it came.
While installing be careful it does not go close to radiator fan.
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Unfortunately, A1155400241 appears to be NLA as well! :(
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I bought it from the dealer on Friday! :)
And I have just ordered another one - Webparts is showing it is available in German warehouse, which means delivery TuesdayWedneday for me.
I ordered this strap because the ABS ground strap in my W463 wos torn somehow and I ordered it last weekend for that purpose. BUt when I picked it Friday, I tried it on Pagoda in the location we just discussed and I figured it fits very well. I fitted it in Pgoda and ordered another one for my W463.
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Unfortunately, A1155400241 appears to be NLA as well! :(
Looks like it is available from this dealer: https://www.mbpartsworld.com/oem-parts/mercedes-benz-ground-strap-1155400241
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Just picked up another one for my W463. Sharing picture for full information for choosing/not choosing it. Length is ca 53cm. Allows for routing so that it does not interfere with battery removal.
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Mine arrived today!! Only 3-4 left in New Jersey in case anyone wants to get one!!
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Which strap, the one from the firewall to the engine/transmission, or the one from the block to the radiator??
The one from the block to the hood spring rest.
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Unfortunately, A1155400241 appears to be NLA as well! :(
There is a company that makes cables like these, with various connectors on the ends. I have a note on them somewhere in my files. I will try to find the name and post it. I also had a conversation with George at Authentic Classics about it, a year or two ago and he seemed to be willing to have them made up, if we could get him the details.
My original had fallen apart, so I was looking for a replacement. However, I took the connectors apart and bought a new piece of ground strap and soldered it into the old connectors, and used new heat shrink tubing of the ground strap. That is what I am using now.
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Remember that electricity takes the path of least resistance. These were added as part of the radio interference supression kit. Also added was a small capacitor on the coil bracket. Both of these would route the ignition coil potential away from the firewall and antenna side of the car (near the dash where radio sits). When the plugs fire the energy has a straight path back from the block to the coil. So it would make sense that the strap was installed on the coil bracket. This was also the time transistor radios were coming on the market so MB may have been experimenting with the groundstrap location for optimal performance of the radio. I have seen them installed at both locations. 12 years of production leaves plenty of opportunity for production changes.