i still have it
Air Recirculation system broken actuator parts - DIY fixes
- Thread starter TV Sprinter
- Start date
1Latahrog
New member
I also had a broken actuator arm. Went to local wrecking yard and salvaged actuator assembly from a Fed Ex truck wreck. $35 As BC339 points out. It is harder than you'd think! MB and most new vehicles will not allow recirc. indefinitely, usually open recirc door after 10-20 min. Must be a way to overide?
There is a Youtube video on this problem.
https://www.youtube.com/watch?v=Js-k8VKgZCY
search Sprinter air box
https://www.youtube.com/watch?v=Js-k8VKgZCY
search Sprinter air box
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Midwestdrifter
Engineer In Residence
The recirculate actuator has a vaccuum control solenoid that is connected to the Temperature control head unit. This is a simple 12v on/off control signal. If you pull the center console out you can access the wiring harness for the ATC unit. Cut the correct wire and connect it to a switch. When the solenoid receives 12V the recirculate door is closed.
I did this in my van as recirculation is a requirement in the hot and humid south.
I bought my van with a broken housing (not bellcrank, go figure?). I made a shadetree fix with some epoxy and a bolt/plate combo. I didn't want it breaking on the road so I ponied up and bought a new duct/housing for $140. This came with the recirculate flap and bellcrank.
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doug022984
Sporadic Member Since 2015
I thought I'd toss in my low-cost repair for this lever / belcrank or whatever you want to call it. Mine was also broken and looked almost identical to bc339's in post #12 of this thread. I didn't want to spend $50 on a 3D-printed one nor did I want to whittle one from a block of Delrin I had laying around (although I did think about it). I was inspired by Aqua Puttana's mention of using a nail. I mic'd the OD of the good pin at exactly 5.0 mm (knowing Mercedes would use metric everything) or 0.196". I wanted something close to that diameter but couldn't find any nails that size and didn't have any M5 metric bolts with shanks laying around. A #10 bolt shank is 0.145" diameter, so a little small. I settled on a 3/16" diameter (0.187") drive nail anchor (pictured) for $0.33 at ACE hardware.
Then I had to drill a 3/16" hole in the arm. I didn't trust myself using a drill accurately without messing up, so I used a 3/16" endmill since I'm fortunate enough to have access to a machine shop.
Hacksaw off both the ends of the drive nail anchor after measuring the length you need, leaving the head on; insert it in the hole from the back side and then Q-bond the $%&@ out of it for reinforcement. You're left with a pin that's stronger than the plastic one on the other side. If you've never used or heard of Q-Bond, GET IT! I haven't found anything better for repairing/reinforcing little plastic auto parts.
Then I had to drill a 3/16" hole in the arm. I didn't trust myself using a drill accurately without messing up, so I used a 3/16" endmill since I'm fortunate enough to have access to a machine shop.
Hacksaw off both the ends of the drive nail anchor after measuring the length you need, leaving the head on; insert it in the hole from the back side and then Q-bond the $%&@ out of it for reinforcement. You're left with a pin that's stronger than the plastic one on the other side. If you've never used or heard of Q-Bond, GET IT! I haven't found anything better for repairing/reinforcing little plastic auto parts.
Attachments
lever parts given today, gone to Pennsylvania.
I discovered that both my 2004 and 2006 diverter doors were inoperative. The 2004 A/C doesn't work. The 2006 A/C does work. For hot humid days re-circulation helps the cooling to keep up. That's one I wanted to repair.
After reading this thread I went out and investigated.
The 2004 bell crank was hanging loose off the vacuum actuator. The 2006 bell crank pivot had broken off the pin on the door slotted lever end.
Not bad. I removed the 2004 pivot and attempted to install it on the 2006. I was having some trouble until it occurred to me to start the engine and activate the re-circulation. With the engine running the vacuum actuator and spring pulled nicely out of the way.
After some messing around the pivot was installed. I carefully levered the slotted arm over the pin with a screwdriver. After that was installed I popped the re-circ vacuum hose off the power brake assembly and re-installed the vacuum control on the pivot pin.
My opinion is that the return spring is too heavy, and possibly that the travel when pulled in for re-circ pulls too far. My 2006 had a broken pivot crank. The 2004 has a broken slotted arm piece. All that the actuator needs to do is move a door. Why is so much force used that it breaks plastic parts? I greased all the parts with silicone. It may help.
So my 2006 is operating until the next part breaks. My 2004 will likely never get the attention that it should. Given no A/C, wired into place works fine for the 2004.
vic
Added:
I removed the vacuum line from the 2004 and plugged both open ends. I figured that there was no reason to leave a useless vac supply connected to the out of service actuator.
After reading this thread I went out and investigated.
The 2004 bell crank was hanging loose off the vacuum actuator. The 2006 bell crank pivot had broken off the pin on the door slotted lever end.
Not bad. I removed the 2004 pivot and attempted to install it on the 2006. I was having some trouble until it occurred to me to start the engine and activate the re-circulation. With the engine running the vacuum actuator and spring pulled nicely out of the way.
After some messing around the pivot was installed. I carefully levered the slotted arm over the pin with a screwdriver. After that was installed I popped the re-circ vacuum hose off the power brake assembly and re-installed the vacuum control on the pivot pin.
My opinion is that the return spring is too heavy, and possibly that the travel when pulled in for re-circ pulls too far. My 2006 had a broken pivot crank. The 2004 has a broken slotted arm piece. All that the actuator needs to do is move a door. Why is so much force used that it breaks plastic parts? I greased all the parts with silicone. It may help.
So my 2006 is operating until the next part breaks. My 2004 will likely never get the attention that it should. Given no A/C, wired into place works fine for the 2004.
vic
Added:
I removed the vacuum line from the 2004 and plugged both open ends. I figured that there was no reason to leave a useless vac supply connected to the out of service actuator.
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But it might get a partial repair.
It did bug me that I had to wire the 2004 re-circ door. After some cogitation I decided that a rubber link might work on the broken crank arm end.
Close to the end of the broken crank section I drilled a 5/32" hole. I then pushed a Harbor Freight O-ring Set 8.8 mm x 1.9 mm O-ring through the hole and passed it back through itself to form a small loop.
On the 2004 diverter door I stretched the loop over the end of the broken door lever arm. (Fortunately the broken leftover door arm still has a right angle at the end.)
After the loop was secured I started the van and enabled Re-circ to pull the vacuum operator out of the way. The crank assembly then easily popped into place on its shaft. The diverter door moved with manual operation. A good sign.
I removed the brake tap vacuum hose to extend the operator, connected the operator to the crank, and re-connected the vacuum hose. The door moves to open and closed as it should.
For certain the door doesn't seal OEM tight in the extreme positions, but it moves very close to the OEM air flow positions when operated.
The O-ring will eventually fail. It may work for some time though.
vicAdded:
A similar rubber link may work on a broken crank end with an intact door arm. The O-ring staying in place will depend upon the angles of pull.
Fuzzy poor picture of the O-ring.
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Your re-circulation operator has failed.
What if you decide to just wire the door to one position or do nothing? (It isn't the end of the world.)
From another thread.
What if you decide to just wire the door to one position or do nothing? (It isn't the end of the world.)
From another thread.
Added:As was mentioned. it depends upon where the door is positioned.
Wired/sealed to outside air.
Positioned in (furthest from you) it will always be on outside makeup air. During really hot/humid ambient temperatures the A/C may not keep up well because it is always pulling hot moist air which is hard to cool.
Wired/sealed to re-circulation.
Positioned out (closest to you) the blower will always be pulling air from inside your vehicle cabin (re-circulated). During hot/humid ambient conditions the A/C will keep up better because the already cooled and dehumidified air is being re-circulated back to the blower. With no outside (makeup) air being pulled in the air quality may be compromised. Older vehicle air conditioners didn't use full outside air. If you seal the diverter door to re-circulation and are concerned about air quality, crack a window. (Does your home air conditioning system have outside makeup air? Most don't.)
Assuming a typical operator lever assembly failure, the diverter door swings freely. That results in a combination of air sources being pulled in by the blower. The outside air has less resistance to flow so mostly you will get outside air.
The position of the re-circulation door doesn't affect the operation of the cabin inside vents or diverters.
vic
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Can someone confirm if the bellcrank part comes as part of the actuator if purchased, or part of the fresh air housing/assembly?
One reference above implies it comes with the fresh air housing, but wanted to confirm if someone knew. Just wondering if I order a new actuator if that will come with the bellcrank piece.
One reference above implies it comes with the fresh air housing, but wanted to confirm if someone knew. Just wondering if I order a new actuator if that will come with the bellcrank piece.
GaryJ
Here since 2006
Here's a couple more failures of the troublesome recirc system: I'm taking my 06 140 to Bonneville Speed Week in a few days and I was aware that the recirc system had failed on it. Temperatures all the way across Nevada will be in the high 90's to a 100 next week. When I looked at the bell crank, sure enough it was broken off where the pin engages into the door lever arm.
To get a better idea of how the system was supposed to function I decided to have a look at my 06 chassis motorhome. What do I find there but all the parts intact, except the pin on the bell crank is sitting in front of the door lever arm, not in the slot! I started the engine, pushed the recirc button and was able to get the bell crank pin put back in the door arm slot. I lubed it generously and tested it through a number of cycles and it worked well. After looking the mechanism over I think a lack of lubrication between the bell crank pin and the door arm slot may increase the friction enough to add to the likelihood of a failure. If yours is functioning, lubing it may save you a lot of grief later.
As for my 140, unless I get inspired to repair the bell crank before I leave, a very small bungee cord hooked in the door lever, then up through the clip that holds the windshield washer tube and then down to an attachment point will suffice to close the door for the long drive across Nevada.
If you're within a days drive of Wendover Utah, and are fascinated by creative engineering on wheels then by all means don't miss this event. Last year it was $50 for a week long pass, camping is free on nearby BLM land and you can be anywhere along the first 5 miles of the course, from the starting line to the pits. Incredible event!
Gary
To get a better idea of how the system was supposed to function I decided to have a look at my 06 chassis motorhome. What do I find there but all the parts intact, except the pin on the bell crank is sitting in front of the door lever arm, not in the slot! I started the engine, pushed the recirc button and was able to get the bell crank pin put back in the door arm slot. I lubed it generously and tested it through a number of cycles and it worked well. After looking the mechanism over I think a lack of lubrication between the bell crank pin and the door arm slot may increase the friction enough to add to the likelihood of a failure. If yours is functioning, lubing it may save you a lot of grief later.
As for my 140, unless I get inspired to repair the bell crank before I leave, a very small bungee cord hooked in the door lever, then up through the clip that holds the windshield washer tube and then down to an attachment point will suffice to close the door for the long drive across Nevada.
If you're within a days drive of Wendover Utah, and are fascinated by creative engineering on wheels then by all means don't miss this event. Last year it was $50 for a week long pass, camping is free on nearby BLM land and you can be anywhere along the first 5 miles of the course, from the starting line to the pits. Incredible event!
Gary
Jodean
Member
mine was just popped out of the slot, took some pressure to get it back in...
Thoughts on recirc?? I cant find for the life of me think of a time i want fresh air, the AC and the heat on this thing do not work that great, after the 15 minutes i can tell when i breathe in the humid air that the door opened, and it suddently got warmer and humid. On the other hand, in the winter, when its -10F, i also dont need any fresh air.
I say glue the damn thing shut!!! I even put a curtain right behind the seats to try to keep heat/cold in the front. The sprinter REALLY sucks at not getting heat unless you are goind down interstate, hate that the motor doesnt heat up even with the radiator blocked off with plastic sheets. I cant believe they dont stop the flow to the radiator like most vehicles to get some heat for the cabin. The radiator is full flow full temp even when its -10F......no good!!! My old 6.2 and 6.5 were kinda like that also, constant flow to radiator, themostat only blocked some flow......
Thoughts on recirc?? I cant find for the life of me think of a time i want fresh air, the AC and the heat on this thing do not work that great, after the 15 minutes i can tell when i breathe in the humid air that the door opened, and it suddently got warmer and humid. On the other hand, in the winter, when its -10F, i also dont need any fresh air.
I say glue the damn thing shut!!! I even put a curtain right behind the seats to try to keep heat/cold in the front. The sprinter REALLY sucks at not getting heat unless you are goind down interstate, hate that the motor doesnt heat up even with the radiator blocked off with plastic sheets. I cant believe they dont stop the flow to the radiator like most vehicles to get some heat for the cabin. The radiator is full flow full temp even when its -10F......no good!!! My old 6.2 and 6.5 were kinda like that also, constant flow to radiator, themostat only blocked some flow......
Midwestdrifter
Engineer In Residence
The damper can be wired shut. If you are getting radiator flow before about 180F, you need a new thermostat.
Jodean
Member
Really? I just assumed thats how it was, yes radiator is always warm
Midwestdrifter
Engineer In Residence
The thermostat will block 95% of the flow to the radiator before its opening temperature.
Big thank you to MillionMileSprinter for sending me a replacement vacuum tube for the actuator after some rodents found it tasty.
I also was able to repair the “linkage” with some plastic adhesive from JB Weld. I wanted to add that re-installing the linkage, and then the actuator, is no small feat. One of the most frustrating projects I have performed so far. If it breaks again, I am not sure all the bloody scratches and cursing are worth repairing again!
I also was able to repair the “linkage” with some plastic adhesive from JB Weld. I wanted to add that re-installing the linkage, and then the actuator, is no small feat. One of the most frustrating projects I have performed so far. If it breaks again, I am not sure all the bloody scratches and cursing are worth repairing again!
owner
Oz '03 316CDI LWB ex-Ambo Patient Transport
Has anyone thought about somehow reversing the bellcrank/actuator/spring mechanism so that the door is open when the button is pressed, and is in recirc by default? I though about doing this by swapping over the actuator to bellcrank pivot. It would require a slight re-mounting of the actuator, but other than that it should just work*.
Only thing is the notch on the mechanism that slightly locks it into the active state. I guess this is to unload the mechanism and actuator a bit when it is active. This would need a bit more rework to get that working, but then you presumably wouldn't be running the recirc button (which is now the fresh air button) for all that long compared to recirc.
Also, there might be a setting in developer star diag to disable the cancelling of recirc. There was such a setting on my ML270. I can't remember exactly what it was called but it was for desert mode or something for middle eastern countries.
Only thing is the notch on the mechanism that slightly locks it into the active state. I guess this is to unload the mechanism and actuator a bit when it is active. This would need a bit more rework to get that working, but then you presumably wouldn't be running the recirc button (which is now the fresh air button) for all that long compared to recirc.
Also, there might be a setting in developer star diag to disable the cancelling of recirc. There was such a setting on my ML270. I can't remember exactly what it was called but it was for desert mode or something for middle eastern countries.
One concern that I would have is possible easier access for rodents. When the system is working, the door is closed to the interior air system. The rodents can still get in past the squirrel cage fan, but it is a bit more of a challenge. (The fan is aptly named in this case. It will at least keep squirrels at bay, but not little cousins.)
Then again, maybe the position of the diverter door really doesn't matter.
vic
Jodean
Member
??? the door is normally open.....pushing the button closes it
so said conversion door would normally be closed, as in key off, better for your rodent idea!