That red dribble - PeachParts Mercedes-Benz Forum

patbob · #1 10-06-2010, 05:39 PM

I've had a bad week that just keep getting worse

To start off, last Tuesday, I'm late for a school function so I hop in and take off, only to observe my car's leaving a trail. Pull over, and it's already got a red puddle underneath it. Yup, its leaving a drizzle of AFT everywhere I go. So I got it parked back in the lot at work (first picture) and trailered it home last weekend.

I'm thinking its the rubber ATF cooler lines, but nooooo.. my week is worse that that.. it looks like someone crimped the ATF cooler hardline with the support next to the passenger side of the oil pan, and now it's worn through and started leaking there (second picture). I'll verify its really leaking there tonight, and not just dripping off the low point, but I'm pretty sure that's the case.

Near as I can tell, that hardline line connects up on the top of the transmission somewhere, which means I'm not going to be able to replace it until next summer at the earliest (dirt and gravel drive, low point, puddle, 9-month rainy season starting).

So, I've got a couple of questions I'd really like some input on:

First question -- is it possible to replace that hardline without removing the transmission? That's my preferred solution, but at the present looks like it's not doable that way.

Second question -- is patching the hardline using a sleeve of transmission cooler line and a half dozen hose clamps a viable solution? Is standard transmission cooler line acceptable for this -- something like this line from NAPA which is rated for +135C constant?

Thanks for any advice, commiseration, kibitzing, etc.

4thesporty · #2 10-06-2010, 05:49 PM

Those clips in your second pic used to have a little bushing in them that kept them from rubbing holes in your cooler lines. Mine did the same thing last summer.

I went to a PNP and got a set of hard lines, cleaned them really well and wrestled them in from under the car. I used a piece of split rubber hose as my "bushing" on the clips.

It's not a hard job, and you don't have to remove tranny for it either. But, it does take some time to snake the new lines in.

andrewjtx · #3 10-06-2010, 05:49 PM

Ouch...

That line doesn't have much pressure in it, does it? Well, I guess if it's crimped it will now have more pressure than normal.

I would say you could try your hand at brazing the hole. Maybe some JBWeld (which should almost be a sponsor of these here forums)?

dude99 · #4 10-06-2010, 05:52 PM

hmmm.. I seem to remember there wasn't much pressure in these lines but I could be wrong. If the pressure is low you could cut out the leaking section and put in a section of rubber line held on with 4 hose clamps (2 on each side0... that would be my solution at least...

patbob · #5 10-06-2010, 05:56 PM

Quote:

Originally Posted by 4thesporty

It's not a hard job, and you don't have to remove tranny for it either. But, it does take some time to snake the new lines in.

Thanks, that's encouraging. You wouldn't happen to have a diagram showing where they connect or writeup, would you? I don't appear to have a diagram, so I'm going by what I can observe, and it looks like that line disappears up towards the top of the transmission someplace. A writeup with pictures would be wonderful too.. I couldn't find one of those either.

thanks.

andrewjtx · #6 10-06-2010, 06:17 PM

I think it goes up over the started then down the passenger side of the bell housing.

Can't find any other pics of the 722 except on eBay:

http://cgi.ebay.com/ebaymotors/TRANSMISSION-MERCEDES-300D-300CD-300TD-TRANSMISSION-_W0QQcmdZViewItemQQhashZitem2eaf0bb05cQQitemZ200505274460QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccesso ries

Check that pic. The big metal line is what you're looking for.

pawoSD · #7 10-06-2010, 06:29 PM

They can be replaced with nothing removed from the car. We had some new ones made by a local shop for about $85 apiece. The passenger side line has the higher pressure as it is the supply line to the cooler.

Diesel911 · #8 10-06-2010, 06:30 PM

Quote:

Originally Posted by dude99

hmmm.. I seem to remember there wasn't much pressure in these lines but I could be wrong. If the pressure is low you could cut out the leaking section and put in a section of rubber line held on with 4 hose clamps (2 on each side0... that would be my solution at least...

The above should work fine. However, you have to use Oil or Transmission Cooler Hose.
I tried using Fuel Hose (not on a Mercedes) as Transmission Cooler Hose and it lasted a little over a month before the Hose started getting mushy.

Out here in S. CA Oreilly's/Kragen Auto parts sells the Oil Cooler hose by the foot. It is part of parst America (advanced Autoparts, Shucks and ****).

Mark DiSilvestro · #9 10-06-2010, 07:49 PM

If you decide to splice with rubber cooler/PS hose, try to find fuel-injection hose-clamps, as ordinary fuel-lne screw-clamps tend to chew into the rubber hose.
Alternately, if your metal line is very close to an SAE size, (e.g. 8 MM = 5/16", 9 MM = 3/8") you may be able to splice it with a brass compression union, availible at autoparts or hardware/plumbing stores.
Of course, any splice will require relocating the support bracket. Wrap the metal line at the new location with some rubbr hose or several turns of electrical tape to prevent future damage.

Happy Motoring, Mark

patbob · #10 10-06-2010, 08:13 PM

Quote:

Originally Posted by Mark DiSilvestro

If you decide to splice with rubber cooler/PS hose, try to find fuel-injection hose-clamps, as ordinary fuel-lne screw-clamps tend to chew into the rubber hose.
Alternately, if your metal line is very close to an SAE size, (e.g. 8 MM = 5/16", 9 MM = 3/8") you may be able to splice it with a brass compression union, availible at autoparts or hardware/plumbing stores.

Thanks for the suggestions. I'll see if I can find such hose clamps if I do the cooler line splice, which I'm seriously considering as a temporary measure so I can get it drivable again until I can address the hardline replacement.

Quote:

Originally Posted by pawoSD

They can be replaced with nothing removed from the car. We had some new ones made by a local shop for about $85 apiece. The passenger side line has the higher pressure as it is the supply line to the cooler.

Thanks pawoSD & andrewjtx. That's what I wanted to hear

. I haven't seen too many cooler line replacement writeups, and none on the hardlines. Shoudl make for an interesting blog writeup when I get to it.

whunter · #11 10-06-2010, 08:13 PM

Quote:

Originally Posted by patbob

Thanks, that's encouraging. You wouldn't happen to have a diagram showing where they connect or writeup, would you? I don't appear to have a diagram, so I'm going by what I can observe, and it looks like that line disappears up towards the top of the transmission someplace. A writeup with pictures would be wonderful too.. I couldn't find one of those either.

thanks.

Graphic attached.

JHZR2 · #12 10-06-2010, 10:18 PM

Bummer. I remember Marshall Booth mentioning this to be an issue over on the MBCA mailing list years ago.

When I had my oil pan down I took some sheet rubber stock and made a new one. Seems like a prudent move.

whunter · #13 10-07-2010, 02:17 AM

Quote:

Originally Posted by JHZR2

Bummer. I remember Marshall Booth mentioning this to be an issue over on the MBCA mailing list years ago.

When I had my oil pan down I took some sheet rubber stock and made a new one. Seems like a prudent move.

Excellent preventive maintenance on your part.

This issue is an hour or less DIY.

* Cut out the damaged section of the tube.
* Slip on a slightly over size piece of fuel hose for insulation.
* Install a compression fitting.
* Use Perforated Galvanized Steel Pipe Strapping on the fuel hose to make an insulated clip/bracket for mounting from a different oil pan bolt.

Paulc66t · #14 10-07-2010, 09:06 AM

I did a similar repair on my truck when I couldn't locate the correct lines from the dealership or other sources. I went to a brake supply shop and purchased hardlines with the correct fiittings and ID. After bending them into shape(using old lines as a pattern) I joined the front and back using a short section of hose and two clamps on each side. It has held up for 6 months very well.

patbob · #15 10-09-2010, 07:06 PM

Thanks all. I opted for the temporary splice as a repair to get it done before the rainy season started (i.e. today). Here's a few pictures...

That red dribble-squirting_640x480_dscn9363.jpg

The problem, with the engine running. I removed some of the rotten rubber from the bracket and its pretty much squirting ATF now.

That red dribble-holeincoolerline_640x480_dscn9366.jpg

Here's a good picture of the damage. You can see the hole in the cooler line -- its not quite as big around as a pin.

That red dribble-finishedtemporaryrepair_640x480_dscn9378.jpg

The completed repair. The engine's running and not even a drip.

I don't think this solution will last as many years as the original did, so I'm considering it to be temporary. All it needs to do is last until next summer, when I can replace the line altogether.

I don't have pictures, but it looks to me like the bracket was intentionally crimped, probably to tighten it down on the rubber and the tubing. Unfortunately that crimp appears to be the root cause of the problem. It created an inward protrusion that eventually rubbed through the rubber and then the metal of the line. The other side is the same, but not leaking yet. Like JHZR2 did and whunter pretty much recommended, if I get a break in the rain, I'll be replacing the rubber in that one too.. before it causes an identical failure.