jkowtko

Just reading through all of the threads that show how to flush the torque converter through the cooling lines.

The DIY threads show attaching a 1/2" vinyl hose flush line to the cooling line where it attaches to the radiator.

The Service bulletins instruct you to connect the hose using an adapter at the banjo bolt connector where the cooling line returns to the transmission.

The radiator connection might be a simpler place to attach the hose, but it leaves dirty fluid in the radiator and the return line. The banjo bolt connection seems the best place to completely flush out all fluid, but the adapter seems impossible to find ... and I don't know if messing with the banjo bolt can result in leaks.

Questions:

Q: using the radiator connector drain method, is there a good way to clear the radiator and return line of old fluid so you can get as complete a flush as possible? Will the old fluid get "sucked" through the return line as the transmission pumps it's fluid?

Q: using the banjo bolt connection method, has anyone found an adapter? The closest thing I have found for a reasonable price is http://www.mytoolsforyou.com/automot...STR-60238.html

but the ID of the exit hole seems rather smaller to accommodate the amount of trans fluid that will be pumped out when flushing. It would also be nice to have a 90 degree elbow on this connector.

Q: I have thought of an alternative to the banjo bolt adapter ... use an M14x1.5 jam nut to remount the bolt onto the banjo connector while disconnected from the transmission, and since the jam nuts are thin it may leave enough bolt shaft exposed to clamp a vinyl hose directly to the end of the bolt. Has anyone tried something like this?

Q: what is the (ballpark) pressure of the fluid in the cooling lines? Or, how long does it take to pump out 2 qts through the flush hose? Just wondering how tight these connections need to be while flushing.

Thanks. John

C230 Sport Coup

Draining from underneath would be great if you have a lift.
Even then though, you need to jump back and forth starting the car, pumping 2 quarts,
putting 2 quarts in, it's much easier from up top with the car on the ground or rather on
jack stands.
The hardest part of the whole job is the part where you are on your back,
draining, dropping the pan, replacing the orings in the electical connector.

Once that's all done, the rest is cake if you just do it from the rad lines.
Yes, you get it all, takes 12 quarts in but it will come out red and you will know all the old
fluid is gone.

Forget the banjo bolt...what a pain that would be.
Everything you need to do after the pan etc. is from up top, draining, filling, starting the car.

jkowtko

No lift ... just ramps, floor jack and stands. It's kinda tight under there but I should have enough space. I'll be changing out the rear trans mount first so I'll get a good chance to inspect the pan, bolts and fittings under there.

I agree with your comments that flushing from above sounds much easier. I would just like to make sure I'm getting all the fluid.

The hose attaching to the top of the radiator is the supply line from the tranny. If I connect my flush hose to this one I'll be getting all of the fluid in the torque converter and the supply hose, but I won't be getting the fluid in the radiator or the return hose.

If I also disconnect the bottom line from the radiator I should be able to drain the old fluid out of the radiator as well. But I would not be draining the old fluid out of the return line, would I?

Thanks. John

C230 Sport Coup

There's 9 quarts in there total.
The tiny amount left in the line, compared to either the 'lifetime' no flush needed or
the '4 quart drain and go' anyone else will do is more than enough.
When it comes out clean, you know you are done.
Then check the level and be done with it.
Make sure you put in exactly what you take out, unlike me,
I was tired and drained 2 quarts and put one in and ended up 1.5 quarts short.

Forget the banjo bolts.
Besides the lower hose is sucking fluid, and hence will suck the dirty fluid out of the rad and lines, and eventually get regurgitated out.

jkowtko

Not to belabor this, but the remaining old fluid in the return line will get mixed right back into the reservoir of fresh fluid that you just poured into the pan, making it virtually impossible to remove that fluid during the flushing process. I assume that is why the Mercedes service manual recommends draining from the banjo bolt -- then you get all old fluid downstream of the reservoir.

I would still like to ask -- can you say how long it takes to pump the 2 qts of old fluid out during the flushing process ...?

C230 Sport Coup

Yes, I grow weary of you insolence. ;-)
Otherwise known as belaboring the point...to death....

Pumping 2 quarts when you start the engine takes a minute perhaps.

Good luck with your project.
The WIS also shows a special hand tool for gawd knows how much for vacuuming out the lines if you really feel the need to go overboard.

jkowtko

Okay, that's a lot to squeeze out of an 1/8" hole as in the fitting shown above. Sounds like the MB fitting would be needed. I'll swing by the dealership this week to see what they have. Otherwise, looking at the hose clip behind my radiator, that's looking easier to me every day as I wait for my parts to arrive ...

If the cooling lines in the radiator are just the same cooling pipe bent in an S pattern, then overall the cooling line probably doesn't carry more than a cup of fluid. So I guess this isn't very significant relative to the flushing of the torque converter. I just thought it would be nice to "get it all" while I have the car up on blocks and things taken apart ... but it would not be good to strip one of those banjo bolts ...

Did you drain the radiator of fluid when you did this? If so, how much came out?

**UPDATE** The dealership price for the hand pump that contains that fitting is over $300, and they're very hard to come by. So I bought two O-rings for the cooling line to radiator fitting, I will plan to go that route and drain the radiator of fluid in the process. The locking clip/sleeve for the radiator connection is a special order item so I'll just be careful not to break one. But would be nice to have a spare, so if anyone out there can get these in the US please let me know where (or I'll buy yours if you have an extra). Part #A-000-277-05-54 http://mbspecialist.com/mercedes_web...em/0002770554/

Thanks. John

C230 Sport Coup

I'll be surprised if there's anything in the bottom line or the radiator, since when you pour the new fluid into the the sump and pump the old fluid out the top rad line via running the engine, the fluid in the rad and lower line will get sucked into the sump.

I'd doubt it's more than a a couple tablespoons if anything.

Don't forget those banjo bolts aren't normal 'hoses'. The fluid comes out the sides of the connector, what a mess. You can't put a hose over them.
I'd be happy to watch and laugh as you jump and fetch from up and down top to bottom of the car.
Laugh. Not with you. But at you. he he
And I'll be drinking all your cold beer while you suffer needlessly.

Be sure to get one of those concrete mixing pans from Home Depot. That was Splinter's idea.
The whole tranny pan just falls right in after you've already drained (to an oil pan).
Really keeps the mess down. There's still a little fluid in the pan even after you drain, and also the filter to contend with.
Don't forget the copper washer for the plug.

C230 Sport Coup

No one here has ever broken this part. I'm not aware of the outer sleeve being removable.
But you could be the 1st! More for me to laugh at.

Yeah, do not lose the little clips.
All you need is the O-ring.
You do need to take the little frame apart that holds the hood latch to make room to get at the hose.
You are hell bent on making this as complicated and increasing the difficulty factor.
It's not a hard job, technically speaking, but it's definitely a PIA job. Takes a couple hours at least.

jkowtko

That was my initial concern ... the old fluid in the bottom line would get sucked back into the sump and mixed in with the new fluid you just poured in, contaminating it. That makes sense that the service bulletin tells you to make the flush point where the return line bolts to the tranny ... there's no old fluid left between that location and the sump.

Assuming the cooling line follows a hairpin turn pattern inside the radiator, I think we're looking at several feet of 1/4-3/8" ID cooling line ... seems more like a quarter to half cup of fluid. If I drain the radiator by pulling the bottom plug and blowing the fluid out, that reduces the old fluid content to just the 3 foot return line. Then I should be able to manually suck the old fluid out of the return line from the radiator connector end (since I'll have the flush hose on hand anyway) ... that should pretty much get it all.

I don't think I'll be disconnecting the banjo bolt anymore (since I think I can get all of the old fluid now through the radiator connections) ... but what I was originally planning here was to have a female M14 hose barb adapter, the same type that the MB hand pump has. You don't fit a hose over the banjo bolt or fitting -- you bolt the banjo bolt to the female adapter in the same way it's bolted to the tranny. The MB Service guide flush instructions (part 2) has an illustration of this. Fluid chambers are sealed from the outside, and the fluid comes out the barb side of the connector. Then the hose can be connected and be of arbitrary length, run it out the drivers side of the car if you like so you can watch the bottle as you flush the fluid.

Yep, got the pan from Home Depot ... great fit for this job. Bought an extra drain plug and two washers and lock pins. I also bought an electrical plug adapter and gear shift level seal, so I'm set to fix anything down there that could leak fluid.

I do have to go back to the auto store and buy a different trans fluid funnel ... the one I have has too wide a spout at the bottom (by maybe 1/8"), and that filler neck looks pretty narrow ...

splinter

This method worked well on mine:




photos credit tworotorturbo

samaritrey

^ +1

C230 Sport Coup

Sucky Sucky tranny go long time! Me so greasy!

motoman

Messing with banjo bolts unecessarily can drag you to the inferno. If you must , know that new copper washers are mandatory. Surprise, the Harbor Frt jumbo box work for me if the dias are ok. I have even annealed old copper gaskets with a torch. You cannot seal a work hardened copper gasket, including over torque.

Xiaotan98

Thanks everybody at first. I also want to DIY my 2007 C280 4 AMTICK transmission fluid change. I read some suggestions, it seems that flush via the cooling lines is the best way, but, I still don't know where is the cooling lines. Is there anybody would like to take a picture show me where is the cooling lines? Thanks again.

lbk

Can't believe I found this post. I am doing a flush on my C240. I am trying to find some other alternative to draining at the banjo bolt. I was considering draining at the radiator but was uncertain how I would attach a drain hose to the incoming line, or the output on the radiator. It looks like you guys have gone through this same issue. I wasn't able to completely tell what you did here. Would you please elaborate and explain to me how you drained the fluid, and how you attached a drain line. I'd really appreciate it. Thank you.

jkowtko

Okay, forget the banjo bolt method. disconnect the hose at the top of the radiator (there is a slide-out clip locking it in), connect a 1/2" ID plastic hose to the radiator hose, use a screw-type hose clamp to hold it tightly on, and run that plastic hose into your dump bucket.

Don't worry about the radiator connection being open. The fluid in the radiator just runs down to the return line and dumps back into the transmission sump. you might want to get something to let you blow air into the radiator to push all of the fluid in there back into the transmission. Btw, do this before you replace the pan so you can get this last bit of fluid out of the system.

if you are not sure about the flush-and-fill iterations, look under Toyota Sienna and Honda Accord ... there are a handful of good DIY posts on this and it's pretty much the same for any vehicle that as a transmission cooler line.

lbk

Is that connection to the radiator as simple as it sounds? If I disconnect, can I just put it back together and it should seal up? Are the "o" rings there? Just don't want to take it apart and have problems getting it back together properly. Thanks.

jkowtko

yes it's that easy. The slide clip is u-shaped and on my car I had to pry it down and towards the center of the car at about a 45 degree angle, as I remember it. Do it gently with a small screwdriver. Then the hose is just lightly press-fit into the little pipe flange, friction from the o-ring. So wiggle it gently but firmly out of the radiatior coupling. Then you'll see you have about 1/2" or more of pipe insert to fit into your clear plastic hose.

I think you also have to release a plastic clip or two down by the bottom of the radiation that is holding the pipe stationary.

The o-ring cost me $3 at the dealership. The fluid isn't under a lot of pressure going in the cooling lines since it just dumps back into the transmission sump, but safer than sorry to just replace that o-ring to prevent leaking.

lbk

Did u just drain the radiator then. That sounds like the simplistic thing to do. I'd think draining it would be easier than trying to push fluid out of the radiator with a pump.

jkowtko

I just held a piece of hose against the hole where I pulled out the upper cooling line, and blew air in with my mouth. Took two seconds to push the 1/4 cup of fluid out of the line. Real simple.

Again I can't emphasize how easy this is. The radiator cooling lines (unlike engine coolant hoses) are not a high pressure system.

The same goes for power steering for the return lines from the rack back to the PS reservoir ... although running the engine makes the PS fluid come out of the return line too fast. So the trick there is to jack up the front of the car and with the engine turned off but the key in first position to release the steering wheel lock, turn the steering rack lock-to-lock to do a slow pump of the fluid through the system. Same idea with dumping old fluid from the return line. Same easy task.

I think the worst part about these tasks is just catching the dripping fluid before it drops all over everything and makes a mess of your driveway or garage floor. But a little care with rags and using plastic bottles cut in half for a catch basin, works wonders. I've now done all of our older cars this way.

C230 Sport Coup

No, you don't drain the radiator.
Tranny fluid runs through a separate conduit on the side of the rad.
Entirely separate.
Mixing the 2 is a big no no.
Read up on the Valeo radiator disaster from the early 00's.

C230 Sport Coup

Oh you expert now!
Look at you repeating my advice like a parrot.
Well glad you finally stopped over-analyzing and got it done.

jkowtko

Sorry if I repeated you, I didn't reread the last several posts before adding mine ... but repeated and consistent emphasis in posts is also good to help people feel comfortable with a technique that is being promoted.

I did my flush in Nov 2012 successfully, and I've also done the flush on two other cars (both Toyotas) since my posts of 2012 -- so, yeah, I feel more like an expert now

*** update ***

lol - I just read back though the past page of posts and saw that I copied your phrase exactly ... "forgot the banjo bolts!". Sorry, I didn't even see that ... I guess we just use the same lingo. But yes, since those posts where I was paranoid about screwing something up, I did the tranny service on my car and went on to do our two Toyotas as well.

C230 Sport Coup

What happened to the delete button.
Double posted!