front flex disk popped. so did my airbag. - Page 2 - PeachParts Mercedes-Benz Forum

tjts1 · #16 08-23-2013, 07:32 PM

Quote:

Originally Posted by MBeige

At least we know they still work despite the 10-year recommended replacment intervals (assuming they weren't replaced).

You can replace the front with a rear unit I think but the ride won't be as smooth, from what I've read. The front flex disc is desiged this way to "flex" and smoothen/dampen out the vibrations in the driveshaft when changing gears.

Its really not bad with a rear flex disk on the front. The drivetrain just feels a lot less ropy and throttle response is more immediate. I wouldn't have it any other way.

winmutt · #17 08-23-2013, 08:12 PM

Quote:

Originally Posted by DeliveryValve

Oh wow, I thought you installed one of these to prevent that from happening?

No?

.

No, they make a 78mm (bmw) but not a 80mm. Hedghog tuning makes em but hes in malaysia I think. The problem is that I need a 90mm flex disk and am too lazy. Next time around I will get it done.

winmutt · #18 08-23-2013, 08:13 PM

Quote:

Originally Posted by MBeige

You can replace the front with a rear unit I think but the ride won't be as smooth, from what I've read. The front flex disc is desiged this way to "flex" and smoothen/dampen out the vibrations in the driveshaft when changing gears.

I ended up finding a Lemforder "hardened" 80mm. The problem is that I am putting 2x the power that these 80mm's were rated for. I just didn't expect the air bag to part of the problem

pawoSD · #19 08-23-2013, 09:08 PM

2x the power? How so? Do explain.

winmutt · #20 08-23-2013, 10:45 PM

Quote:

Originally Posted by compu_85

You'll need to replace the seatbelts too...

-J

I'll check that they still catch. Didnt think of that!

winmutt · #21 08-23-2013, 10:47 PM

Quote:

Originally Posted by pawoSD

2x the power? How so? Do explain.

The 80mm were used in the NA diesels and smaller gassers. 603 without a cat does 168hp. I've got to be in the low 200's now. Been keeping the ALDA dialed in pretty good to keep from blowing the engine at 6k rpm.

tjts1 · #22 08-24-2013, 12:18 AM

BMW used the 78mm flex disk well past 200hp and they only have one on their cars so the shock loads are higher. The BMW front flex disk is basically identical (other than diameter) to the MB rear flex disk. They have U joint at the back.

jay_bob · #23 08-24-2013, 08:08 AM

Quote:

Originally Posted by winmutt

I'll check that they still catch. Didnt think of that!

I believe the ETR mechanism pulls a spring that sucks the seatbelt in tight and keeps it there.

Remember it is illegal to ship ETRs and airbags by any carrier (UPS/Fedex/USPS) so you will have to hit the yards for spares.

I would also look at replacing the airbag controller (under console) and capacitor unit (in passenger foot well) since I seem to remember reading something about these being one use items.

Maybe a good time to consider a dual airbag upgrade
W124 Passenger Airbag Retrofit Project Completed (with pics)

winmutt · #24 08-24-2013, 08:29 AM

Quote:

Originally Posted by jay_bob

I believe the ETR mechanism pulls a spring that sucks the seatbelt in tight and keeps it there.

Remember it is illegal to ship ETRs and airbags by any carrier (UPS/Fedex/USPS) so you will have to hit the yards for spares.

I would also look at replacing the airbag controller (under console) and capacitor unit (in passenger foot well) since I seem to remember reading something about these being one use items.

Maybe a good time to consider a dual airbag upgrade
W124 Passenger Airbag Retrofit Project Completed (with pics)

going the opposite direction...

gatorblue92 · #25 08-24-2013, 08:50 AM

Quote:

Originally Posted by winmutt

going the opposite direction...

Nice!

BenzDiesel · #26 08-24-2013, 11:57 PM

I admire Winmutt’s ability to put defeats behind him and keep charging full speed ahead. Mercedes cars are full of traps when you start trying to modify something, like installing a high powered diesel engine IP, running high performance oversize wheels and tires, and changing to standard transmissions and changing steering wheels and things like that. Sometimes I think there is a little Mercedes man in each Mercedes car just watching and waiting for you to try to change something from factory specs. On the air bag explosion, I bet the car recognized Winmutt’s alien steering wheel and set the bag off.

winmutt · #27 08-27-2013, 08:22 AM

The seatbelts fired as well. Time for a trip to the junkyard. Is the crash sensor a one use part? Where is it located?

jay_bob · #28 08-27-2013, 08:54 AM

On the 87s there is a control box right below the ash tray. There is also a capacitor unit in the passenger foot well.

I think for 88 or 89 they went to an integrated control and capacitor unit under the ash tray.

I don't know if the wire harness changed between 87 and 88-89 but I bet it did due to not having the separate capacitor any more.

I think the pax air bag came along in 90 and that controller and wiring is definitely different than the 87-89.