|
|
|
#1
|
|||
|
|||
How to drop rear head restraints on W124 300D
I needed to remove the rear seat and had to stop when I could not get the rear seat head restraints to drop using the switch on the dashboard. No bad fuses apparrent.
__________________
87 300D 265Kmi Factory rebuilt crate 603.96x engine at 200K |
#2
|
||||
|
||||
Just because a fuse looks okay doesn't mean it works... if you've never replaced them I'd highly recommend doing just that. Also, the switch could be bad... the sunroof switch on my SD went bad.
__________________
I'm not a doctor, but I'll have a look. '85 300SD 245k '87 300SDL 251k '90 300SEL 326k Six others from BMW, GM, and Ford. Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG] |
#3
|
||||
|
||||
I've got the same problem with my '87. I've checked my switch and it's OK and there's power getting to it. I haven't checked any further than the switch. I've seen somewhere that the headrests are vacuum powered. Could it be be the actuators?
__________________
DJ 84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012 |
#4
|
|||
|
|||
What works for me is to have someone in the backseat force the headrests back while I hold down the switch. It works for me 99% of the time.
__________________
2001 Dodge Ram 2500 Cummins Turbo Diesel - 4x4, auto, 3.54 gears, long bed ------------------------------------- '92 300D 2.5 Turbodiesel - sold '83 300D Turbodiesel - 4 speed manual/2.88 diff - sold '87 300D Turbodiesel - sold '82 300D Turbodiesel - sold |
#5
|
|||
|
|||
They are vacuum actuated. Use your mighty-vac to apply vaccum and they'll drop, or you can just manually push them down.
__________________
1987 300D Turbo 2000 VW Golf TDI 2008 E320 Bluetec |
#6
|
||||
|
||||
I've tried to push mine down manually w/o pushing the button and they won't budge.
__________________
DJ 84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012 |
#7
|
|||
|
|||
Push harder.
I wouldn't do it very often, however.
__________________
1987 300D Turbo 2000 VW Golf TDI 2008 E320 Bluetec |
#8
|
|||
|
|||
Pushing without releasing the lock is NOT a good idea. These are supposed to be able to stay up when they are smacked hard by your head in an accident so they won't (and shouldn't) go down by just pushing them. The switch is electrical but the actuators are vacuum powered. Ifind I sometimes have to hold the switch for as much as 10 seconds to get my headrests to retract. My guess is I have a slight vacuum leak but I've never followed through to fix it. If the electrical circuit is good you need to troubleshoot the vacuum system. DON't just push them down, at least try holding the switch for a few seconds to see if enough vacuum can build to release them. If you break the locking mechanism they'll be useless from a safety standpoint.
__________________
LRG 1987 300D Turbo 175K 2006 Toyota Prius, efficent but no soul 1985 300 TDT(130K miles of trouble free motoring)now sold |
#9
|
||||
|
||||
There are vacuum solenoids under the rear deck, accessible from the trunk. These rarely fail in my experience, and neither does the switch. But there's a switchover valve or "vacuum relay" under the rear seat cushion, on the driver's side, that often fails. To get the cushion out, wiggle the orange release levers and pull it up and forward. It'll be obvious how the system works when you see the vacuum lines and wires under there, and it's easy to figure out what's broken with your voltmeter and MityVac. If it is the switchover valve, a new one is about $25, or was the last time I bought one (they've been bad on every old 124 I've seen).
__________________
AlexTheSeal: hack mechanic, inadvertent drifting champ, builder of infernal devices, professional epistemologist '87 300D Turbo, roadtrip mileage champ (for sale!) '92 Isuzu Trooper, mudder extraordinaire (for sale!) '82 Honda Silverwing, cockroach of motorcycles And various boring daily drivers... Last edited by AlexTheSeal; 09-09-2005 at 05:12 AM. |
#10
|
|||
|
|||
You can hear the solenoids click when you push the button, even if there is no vacuum. Also, mine do not work unless the engine is running which would suggest that the vacuum is supplied from the engine, not the door lock vac pump. You may have a vac leak too and need to use a Mity-Vac to determine if there are leaks.
|
#11
|
||||
|
||||
Quote:
Quote:
__________________
AlexTheSeal: hack mechanic, inadvertent drifting champ, builder of infernal devices, professional epistemologist '87 300D Turbo, roadtrip mileage champ (for sale!) '92 Isuzu Trooper, mudder extraordinaire (for sale!) '82 Honda Silverwing, cockroach of motorcycles And various boring daily drivers... |
#12
|
|||
|
|||
Rear Head Restraint Response
Thanks to everyone for the response. i will go digging under the rear seat for the oft-broken vacuum device.
__________________
87 300D 265Kmi Factory rebuilt crate 603.96x engine at 200K |
#13
|
||||
|
||||
If the vacuum units were broken, wouldn't it affect the entire vacuum system?
__________________
DJ 84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012 |
#14
|
||||
|
||||
Quote:
__________________
AlexTheSeal: hack mechanic, inadvertent drifting champ, builder of infernal devices, professional epistemologist '87 300D Turbo, roadtrip mileage champ (for sale!) '92 Isuzu Trooper, mudder extraordinaire (for sale!) '82 Honda Silverwing, cockroach of motorcycles And various boring daily drivers... |
#15
|
|||
|
|||
I hope you've already fixed this by now; in case you have not, I had a similar problem on my 87 300D Turbo. Dropping the head rests requires vacuum from the vacuum pump, & I suspect you have a leak somewhere in the vacuum system. You can test this, but I was never able to find a schematic that told you what the vacuum should be throughout the system. But you can use a Mityvac to provide vacuum to the system to see if you have a leak and/or if the rests will drop under vacuum.
In my case the leak was in the EGR system--I had a bad vacuum valve transducer that leaked, so the vacuum going to the head rests was not sufficient to drop them. On my 300D, there are 4 small plastic vaccum lines coming out of a rubber "X" fitting on the front of the vaccum pump. When you face the front of the engine, 2 lines go left (to the EGR/vaccum transducers), and 2 go to the right. One on the right feeds the transmission vacuum amplifier, and the other feeds the "accessories" line that powers/drops the rear head rests. I fixed my problem by pulling the EGR vacuum lines out of the rubber "x" fitting on the vacuum pump, joining two short pieces of plastic vacuum hose joined together with a piece of rubber hose to make a "U" and inserting the ends of the vacuum tubing into the "x" fitting to bypass the leaking EGR transducers. Good luck. Frank |
Bookmarks |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
1978 300d Cyl Head availability & $$$$ | ajb | Diesel Discussion | 4 | 01-12-2005 04:40 PM |
W124 Rear Subframe Mount Question | John Plut | Tech Help | 1 | 11-27-2003 12:09 AM |
380SEL replace 6 bent valves or used head? | New2MBZ | Tech Help | 0 | 07-30-2003 01:17 PM |
////AMG Rear Bumper for W124 4 Sale!!! | FA22 | Mercedes-Benz Used Parts For Sale & Wanted | 2 | 06-24-2003 02:47 AM |
1992 300CE w124 - rear head rest won't lock up | mushedroom | Tech Help | 3 | 06-05-2002 09:38 PM |