Finishing Samson the M120 R107 - Page 8 - PeachParts Mercedes-Benz Forum

Roncallo · #**106** 08-14-2020, 10:23 PM

The harness is out and the replacement harness came in. The other parts are starting to come in. First step will be to lay out circuit protection to the new harness. In my case I need protection for both the 107 side of the harness as well as the 129 side. Those will each be 60 Amp fuses. In addition a better solution to the electric fan will be implemented. I would also like to leave room for one more fuse in the event I were to install high performance lighting. So the challenge is to find some reasonable room under the hood to mount 4 MIDI fuses on a buss bar. Preferably the fuses should be in-sight and mounted as close to the X4/2 terminal block (Black thing) shown in each picture. Looks like the in-sight part is not going to happen. So next best thing is accessible by removing only the air intake rubber boot for the right side air intake.

Next thing to do is to finalize all modifications to the harness and re wrap the harness with modifications in place. This is the hard part, not physically doing it but going over all the design choices required to make the change. I find myself weighing all the pros and cons of different wiring paths.

After reviewing all the options for warping the wire harness, I came up with Tesa 51036 tape for the engine compartment. It was kind of strange going through the Tesa tape properties and coming up with 51036. Then when I went to search for a place to buy it I got an add from Amazon stating this was the standard OEM tape used by MB, VW etc. Some time me and Mercedes think alike.

https://www.amazon.com/gp/product/B01I2MLN2Q/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

Aside from high temperature wiring harness tape. Tesa also sells tape for inside the cabin with the focus on reducing noise. I may investigate that as well but for the life of me I don't know how wires make noise unless they are being flexed.

vwnate1 · #**107** 08-15-2020, 09:32 PM

60 amperes is pretty high ~ what consumer will draw that much ? .

As it's a custom job, maybe consider circuit breakers ? .

Roncallo · #**108** 08-16-2020, 10:45 AM

Quote:

Originally Posted by vwnate1

60 amperes is pretty high ~ what consumer will draw that much ? .

As it's a custom job, maybe consider circuit breakers ? .

I'm going to start with 60 amps and reduce after taking measurements. The wire is 10mm2 ~ 9gaAGW. Since the goal is to protect these wires and only these wires , I can fuse to the maximum Ampacity of the conductors.

Also you are correct, since these wires are bundled the Ampacity goes down. In the end they may very well be two 40 amp fuses since the current is now divided between the 107 wire harness and the 129 wire harness

The 107 side has all the lighting and body electrics. The 129 harness caries all engine and Aux fan.

Circuit breakers are not being considered because these Circuit 30 (power on at all times) and should be sized so that if there is any problem, something really does need to be repaired

vwnate1 · #**109** 08-16-2020, 01:39 PM

Sounds like you've got things well in hand .

I'm not afraid of electrical so I used to get the hard jobs and screwups, fires and so on....

Roncallo · #**110** 08-18-2020, 11:53 PM

I had kind of a major break through today. I was looking for someone who could laser or water jet the flat panels needed make the circuit 30 fuse block mount. I was trying to find someone local that could have done it today but instead I found an outfit called SendCutSend.com. They were able to take my drawings and instantly provide me a quote. They have a minimum order of $29 so I had to order 2 copies for $29 which includes shipping.I cant even buy new steel for that price when you factor in shipping. So this morning I ordered 2 copies of the flat panels, see the attached PDF, I need to make the fuse block mount. They say they will be shipping them Monday morning. For the record Xometry quoted me $250 for 1 set with about a 2 week delivery time.

Other than that I completed the analysis of the wire harness as far as which conductors to remove from the R107 harness because those wires are for features that have been off loaded to the R129 harness. The main conductors to be removed are from the connector X26 which mounts way up in the top right corner of the passenger side of the fire wall. X26 is a 14 pin connector of which only 2 will be used and a third will be reassigned to the airpump. Two other conductors to be removed are the one that went to the M117 ignition coil and the diagnostic socket. A repair is also required for the conductor going from the ignition switch to the X27 connector on the engine side firewall. I may opt to repair it or replace the whole conductor with a spare I have from one of the other harnesses.

I'm held up a bit until the week end as I am waiting for more small parts and tools before I can attempt to start warping this harness. In the mean time I got come shrink tube labeling tape for my labeling machine and will start labeling all the connections at the fuse box and everywhere else. That is a fairly big job in itself. But I get to remove all those blue tape labels I put everywhere.

Also I discovered a new way to solder these pins onto the wires. Iv'e always had a problem of holding the pin while soldering and the vice grip I would hold it with would suck the heat out of everything. So I took a piece of wood and just drilled a hole about 1/4" deep to hold the pin while I solder. It works very well. I can now put as much pressure as I want on the pin with the soldering iron without the pin running away from the or getting the heat sucked out of it with a metal tool.

I also found a good way to open up the ignition switch connector. It has 6 locking tabs that all need to be disengaged at the same time. So I wedged 6 small pieces of 0.020 AL into the locking tabs then I was able to work it open with a screw driver.

vwnate1 · #**111** 08-19-2020, 02:01 AM

Very nice .

Roncallo · #**112** 08-25-2020, 12:08 AM

For the last two days I have been working on a mount for what is known as the Base module from the R129. Not sure what the Base module does but it talks to all the other computers used in the later model Mercedes. I completed a rough cut mock-up today. Now I can tweek everything and make a final design to have laser cut. This will make the Base module easier to remove for service. There are fuses on the Base module so easy access is good and hopefully I wont stress the rest of the wires getting at it.

Roncallo · #**113** 08-26-2020, 02:54 AM

Fuse block plates came in today. These guys do a nice job. To make the minimum order I had to get two sets for $29.00. I only needed 1. There will be a final revision to this, so I will be sending it out again when I'm ready with a few more parts. The forward stiffener is going to need to be removed as they are causing chaffing issues with the heater hose. Or I may just bend it up. For the moment I have no means of bending the side stiffener without using a vice and hammer, so it is not shown bent in the pictures. I will also nee to radius the front right corner to give access to the shock nut.

I now have it installed into Ebola, My parts car. Tomorrow I will get the wife to close the hood with me in the engine compartment so I can check clearance with the hood springs.

There is also 1 more fuse block I need to install. It is a small 4 fuse block that uses standard ATC/ATO fuses to replace the ol ceramic ones used for the 560SL alarm system. I will also fuse the power windows and the OVP relay. That will cover all circuit 30 (live at all times) conductors running in the main wire harness.

TBC

vwnate1 · #**114** 08-26-2020, 09:58 PM

As always, looking very good .

Roncallo · #**115** 08-28-2020, 06:29 PM

Quote:

Originally Posted by vwnate1

As always, looking very good .

Thank you sir

It will be about a week before I get my flat patterns back for the base module install. Once I have that complete I can at least start assembling things and hopefully start the engine. There will be a lot more work after that.

But for now its hurry up and wait.

vwnate1 · #**116** 08-29-2020, 01:40 AM

You're doing all the hard stuff, I'm just the student watching, listening and learning .

As the old saw goes : 'there are many different ways to skin a cat' ~ watching this I wonder if giving a tom cat a cold bath might be easier....

.

Roncallo · #**117** 09-02-2020, 11:54 AM

Got a few terminal parts in yesterday and got them installed. Now I'm just sitting here waiting for my flat patterns to arrive for the base module and the new fuse block mount. They are due in today. Hope fully I can get them bent up tonight and painted ready for installation in the morning. I also ordered a piece of copper from Mcmaster to mace a proper buss bar to replace the AGW 8 jumper wire shown in the picture. So for the moment I'm just here twiddling my thumbs.

Roncallo · #**118** 09-03-2020, 11:33 PM

Parts came in all fabrication and painting is now complete. Paint will dry tonight and I can start assembly in the AM. Hopefully wire harness installation can begin on Saturday. Pictures are of new copper buss bar installed and paint drying.

Roncallo · #**119** 09-05-2020, 01:14 AM

Fuse block is complete assembled and fitted to Samson. Base module also complete and installed. Believe it or not that last picture shows the base module installed in Samson. Now if I can get a helper tomorrow, I can start to feed the 18' long Anaconda of a wire harness back into the car.

Roncallo · #**120** 09-06-2020, 09:16 AM

First 10 ft of harness installation went as expected. The first 10 ft goes through the right side fire wall, along the right side fender and then along the radiator support to the left side head light. At his time those wires are in place but still cant be tied down until I get the fuse box mounted. Mounting the fuse box will be the most difficult part. The wires are very crowded in that area and several harnesses converge. Figuring which harness goes on top of which is the key to the puzzle. Once the fuse box is installed I expect the rest of the job to go smooth.