GregMN's 1991 W126 350SDL Has A New Home - Page 6 - PeachParts Mercedes-Benz Forum

ROLLGUY · #76 10-01-2018, 02:38 PM

Quote:

Originally Posted by Squiggle Dog

I have a boost gauge, but I remember looking for a spot on the manifold to hook it up (years ago?) and couldn't find one, so I started working on something else--and here we are. I just have to find where I can attach the boost gauge and go from there.

IIRC, on the left side of the manifold there is the boost connection going to the ALDA. The signal is usually intercepted by some plumbingand/or devices that remove the signal. For testing (or permanently if desired), I would plumb it directly from the manifold to the ALDA. Much of the plumbing and devices are for smoothing out the shifting, thereby removing boost while shifting. This is all good if everything is working properly, but my guess is that is not the case. I like to simplify the vac and boost pluming on these cars, and get to the bare minimum. All you really need is a vac signal from the VCV to the trans modulator, and a direct boost signal from the manifold to the ALDA. A pressure waste gate is a must as well. I don't have a 603 anymore, so I can't take detailed photos to show the parts.

Diseasel300 · #77 10-01-2018, 05:41 PM

Quote:

Originally Posted by Squiggle Dog

I have a boost gauge, but I remember looking for a spot on the manifold to hook it up (years ago?) and couldn't find one, so I started working on something else--and here we are. I just have to find where I can attach the boost gauge and go from there.

Get a T or a Y vacuum fitting and tie in at the manifold. There's a little nipple fitting with a vacuum line attached to it above the cruise control servo. The line goes to the switchover valve on the firewall and then down to the ALDA on the IP.

Squiggle Dog · #78 10-01-2018, 06:04 PM

I removed all the ALDA-related vacuum components and gutted the ALDA itself years ago. Right now there is a plug on the manifold where the vacuum tubing would have gone. I'll probably run it from there.

ROLLGUY · #79 10-01-2018, 09:10 PM

Quote:

Originally Posted by Squiggle Dog

I removed all the ALDA-related vacuum components and gutted the ALDA itself years ago. Right now there is a plug on the manifold where the vacuum tubing would have gone. I'll probably run it from there.

It is probably just over fueling, and the turbo is fine. I would put an ALDA back on, and hook it directly to the manifold if it were mine. Without the ALDA, you have no way to control the amount of fuel. The boost signal is supposed to do that.

83w126 · #80 10-02-2018, 11:32 PM

If you are going to be rebuilding the front suspension, you may want to order the tab nut parts that hold the guide rod mount bracket to the frame soon. There is not really a usable aftermarket solution, and when I just recently rebuilt the whole suspension on my 300SDL the dealer had only a couple sets left anywhere in the whole country.

Squiggle Dog · #81 10-17-2018, 02:25 AM

Quote:

Originally Posted by ROLLGUY

It is probably just over fueling, and the turbo is fine. I would put an ALDA back on, and hook it directly to the manifold if it were mine. Without the ALDA, you have no way to control the amount of fuel. The boost signal is supposed to do that.

Interesting. I disabled the ALDA on my W116 300SD and it has lots of power and almost never smokes, even at full throttle.

Quote:

Originally Posted by 83w126

If you are going to be rebuilding the front suspension, you may want to order the tab nut parts that hold the guide rod mount bracket to the frame soon. There is not really a usable aftermarket solution, and when I just recently rebuilt the whole suspension on my 300SDL the dealer had only a couple sets left anywhere in the whole country.

Oh, okay. I know one of the tab-nuts is actually just a nut welded onto a custom-made bracket that's replacing the subframe mount that rusted off.

Squiggle Dog · #82 10-17-2018, 02:29 AM

My roommate ordered a used light control module on eBay, and this is what showed up. The shell is cracked and the circuit board is broken. I would say that it got damaged in shipping, but it was wrapped very well in bubble wrap and it almost looks like someone tried to glue the shell.

This part is no good. Fortunately, the seller refunded his money. What's interesting is that after I put the original one back in and turned on the lights, the high beam indicator light was no longer stuck on, and the high beams worked again. Strange. Simply removing and then reinstalling the control unit seemed to fix the high beams.

Squiggle Dog · #83 10-17-2018, 02:37 AM

The sunroof was sticking and has been leaking, so I inspected it. The external felt seals are in good condition, but the sunroof is designed with a tray so that even if the seals leak, the water is routed down the tray and out drain hoses that are located at each corner. The tray had no rust and only light sediment on it. It was odd that it was leaking as I was expecting either rust holes or clogged drains.

I cleaned the tray and after pouring a cup of water in several places, I found that water at the front center section of the tray wasn't reaching the drains fast enough, so it was overflowing. I couldn't see this area of the tray well, so I had to remove the spring-loaded wind deflector. Once this was out, I removed the plastic brackets that clip on each front corner.

Once these were gone, I could see that the water is supposed to flow through a small tunnel underneath the welded-on metal bracket that holds the plastic brackets. This was plugged with sediment. So, I cleaned them out which allowed the water to flow freely to the drains.

The wind deflector clipped back into place with the plastic brackets attached.

I lubricated the tracks with what is supposed to be the correct non-sticky ATE Plastilube grease.

The sunroof headliner was soaked and dripping with water. I removed it so it could dry and I could see why the tilt function of the sunroof wasn't working.

I lubricated the tilt function of the sunroof and it now works again. It's also possible that the switch contacts were tarnished from non-use.

Squiggle Dog · #84 10-17-2018, 02:41 AM

Letting the headliner dry.

The headliner back in place.

The sunroof functions smoothly and tilts, so now he doesn't have to buy a convertible. Haha.

I cleaned and polished the aluminum metal trim at the front because it was oxidized and corroded.

Squiggle Dog · #85 10-17-2018, 02:48 AM

My roommate called me today as he was leaving from work and said that the front end of the car felt like it was going to fold under. The first thing I noticed was that his two year old tires weren't in good shape. He got a new pro-rated tire to replace the left rear under warranty.

The left front tire was dry rotted and the sidewall split, so it was replaced by the spare tire in the trunk.

Almost a year ago, one of the bolts and retainer plates that hold on the subframe came loose and fell off, so a replacement was purchased. As I was inspecting under the car, I saw that the bolt and plate were unthreaded and hanging out again. I reached out to touch the bolt and it fell out in my hands. I'm certainly glad it didn't fall out on the road again! This time I cleaned the threads, installed thread locking compound, and tightened it super tight.

One of the subframe mounts on the body had rusted off and the previous owner replaced it with a plate. I looked closely at the plate and noticed it was loose. No wonder the front of the car was moving around so much! The left side of the subframe wasn't even securely attached to the body. I tightened the front two bolts some more, but the box tubing of the body keeps collapsing and the bolts loosen again. They are carriage bolts and the lower rear keeps spinning. Both the rear bolts are so rusty the nuts won't turn anyway.

So, this bracket is going to need revisiting. I think the bracket itself is fine, but it's going to need new bolts with heads that can be secured, as well as steel tubing inside the box tubing so it stops crushing in when the bolts are tightened.

The ball joints are shot, too, so they will need attention very soon. The steering box is also leaking power steering fluid onto the subframe mounts and it's causing them to swell and deteriorate. The front of the car shakes badly above 70 MPH, so more work is ahead.

vwnate1 · #86 10-17-2018, 09:11 AM

THANK YOU for posting the dustless sun roof grease ~ I'll have to order some and do my sun roof .

Those tires ! WTH ?! . what brand are they ? .

You're right about the frame gusseting plates, it's a simple thing to add steel tubes to prevent collapsing of the boxed frame .

Squiggle Dog · #87 10-17-2018, 11:52 AM

Quote:

Originally Posted by vwnate1

THANK YOU for posting the dustless sun roof grease ~ I'll have to order some and do my sun roof .

Those tires ! WTH ?! . what brand are they ? .

You're right about the frame gusseting plates, it's a simple thing to add steel tubes to prevent collapsing of the boxed frame .

I read somewhere that the ATE Plastilube used for brake parts is the same stuff as the expensive Mercedes-Benz sunroof grease. So, that's what I used since we already had some.

Those are Douglas Performance tires from Walmart. They have a 45,000 mile warranty and they had less than 40,000 miles on them, but I think the only reason he was able to get the one pro-rated at all was because he purchased the roadside hazard protection for an extra $10 per tire. They said that was due to the tread depth being so low that they wouldn't have otherwise been covered under warranty. If the tread is wearing off before the warranty period, I would think that would indicate the tire isn't living up to its warranty.

He just wanted a cheap set of tires on there because the front suspension is so worn out and it badly needs an alignment. But, it's so expensive and such a big job that it's been put off for years. There is a lot more money needing to be put into the car to keep it on the road. It's getting difficult for him to drive because the front end is shot, the power steering requires a lot of effort at low speed, the serpentine belt tensioner is worn out, and the acceleration is sluggish.

Squiggle Dog · #88 11-07-2018, 04:28 PM

I am sad to report that despite the sunroof tray being clean, having no rust, and having clean drain hoses wasn't enough to keep the sunroof from leaking again. It appears the sunroof trays on the W126 are far too shallow, and the path which water has to flow is too narrow for water to drain into the hoses rapidly enough.

Water drips from the very front of the sunroof. When I pour water into the front center of the tray, it overflows over the edge before the water can drain to the area where the hoses are.

All I can think to do is maybe cutting off part of the metal sunroof deflector bracket perches and grinding away at the plastic deflector brackets so the water can drain faster, as Mercedes couldn't get it right on such an expensive car, while previous chassis were adequate. I guess it's another example of newer cars not always being better.

Squiggle Dog · #89 11-07-2018, 04:34 PM

My roommate ordered new Bilstein HD 24-005012 front shock absorbers. It was difficult to figure out which part number the heavy duty ones were, as none of the sites selling them seem to specify which is which. Unfortunately, they didn't come with bump stops or dust boots, as they expect you to reuse the ones from the old shock absorbers. But, the shock absorbers that were on the car were aftermarket ones with welded-on metal dust covers. So, they had to go back on while we ordered the needed parts from The Classic Center.

I actually removed some rubber dust boots from the shocks of the W116 280SE parts car I have, but saw that the bump stops on them were crumbling and new dust boots are only about $5 each, so why not just order new ones? One of them had a split, which I filled with Rustoleum LeakSeal. I guess they will be good to have as spares.

The new bump stops (115 323 06 44), dust boots (126 323 00 38), and nut caps (170 323 01 38) arrived from Germany.

Here they are installed on the new Bilstein HD shocks.