In a Bind - PeachParts Mercedes-Benz Forum

Adriel · #1 09-02-2013, 02:42 PM

So, posted a W.T.B. advert, but since this is my daily driver, in a bind, so figure the extra coverage might help.

I decided on Saturday to replace my U.C.A. as tires are squealing in the University parking garage ramps. Each side took about an hour, however, I was tired and not thinking when I believed the manual saying the sway bar bolt takes 65 foot pounds. So now I have to replace the sway bar. Tried an extractor, but never got that far as bolt is too hard to punch and the break means the bit is walking. Tried a 8mm drill bit, but it is as useless as a wood stick because of the hardened steel. Now the only thing to show after an hour is a chewed up end of the sway bar... I rather just replace and be done. So, anyone have a front W123 wagen sway bar?

Thank you in advance!

sixto · #2 09-02-2013, 02:59 PM

Uhh... you're aware just about everything on the firewall including the brake booster and master cylinder has to come off to replace the front sway bar, right? Check the archives for alternatives but I understand welding on a new end is the more rational choice.

Sixto
87 300D

Adriel · #3 09-02-2013, 03:41 PM

Quote:

Originally Posted by sixto

Uhh... you're aware just about everything on the firewall including the brake booster and master cylinder has to come off to replace the front sway bar, right? Check the archives for alternatives but I understand welding on a new end is the more rational choice.

Sixto
87 300D

I have already started, though the battery tray has me stuck... Got to now by a Dremel and cut it off. Filed for an hour and not making progress. Hoping to be able to wiggle the brake lines over, as don't have another brake cap or inner tube.

The repair ends are for 24mm, not 25mm. That mean paying a machine shop with limited Student funds to enlarge and weld. Spring steel isn't something that is every day welding, B.T.W..

Adriel · #4 09-02-2013, 05:03 PM

So, went out and bought a Dremel, going off a friends suggestion of possibly being able to flatten the area. Well, did flatten, but the Dremel got too hot for my liking. I have the hardest drill bit, and just not biting in. There is no other drill bit harder, therefore, if I can't drill the pilot hole, I can't get the extractor started to turn out the broken bit. It also means I can't buy a 8mm drill bit and drill it out. Only option is spend a week and pull the sway bar. Also, need to find one, hopefully used.

Stretch · #5 09-02-2013, 05:12 PM

Sorry to hear of the troubles.

Try a cobalt drill bit with lots of cutting oil and a very slow speed.

(Just in case #1 => The spec for the bolt is 65 Nm - that's just under 48 ft lbs)
(Just in case #2 => wagon W123 sway bars have a larger diameter than the other variants)

Adriel · #6 09-02-2013, 05:27 PM

Quote:

Originally Posted by Stretch

Sorry to hear of the troubles.

Try a cobalt drill bit with lots of cutting oil and a very slow speed.

(Just in case #1 => The spec for the bolt is 65 Nm - that's just under 48 ft lbs)
(Just in case #2 => wagon W123 sway bars have a larger diameter than the other variants)

Stretch, thank you so very much!

Yep, cobalt bit, for which paid a pretty penny for Irwin.

Ah! My manual states 65 foot pounds, so bet a mistranslation, as using Haynes as factory manual is very lacking. Only thing on the front end is how to remove the spindle, I.I.R.C.. Because of this, going to get paper factory manuals in the future; first need to address this and then see how the suspension is.

Tram insisted sway bars were all the same, however, I know better, as true across most if not all the manufactures. In this case, 24mm versus 25mm. I found one, we just need to find the bolts, which aren't standard: M8x1.5 or 1.75, 17mm hex, and 2mm shank. Just nuts!

Stretch · #7 09-02-2013, 05:40 PM

PM sent

whunter · #8 09-02-2013, 05:56 PM

Quote:

Originally Posted by Adriel

So, went out and bought a Dremel, going off a friends suggestion of possibly being able to flatten the area. Well, did flatten, but the Dremel got too hot for my liking. I have the hardest drill bit, and just not biting in. There is no other drill bit harder, therefore, if I can't drill the pilot hole, I can't get the extractor started to turn out the broken bit. It also means I can't buy a 8mm drill bit and drill it out. Only option is spend a week and pull the sway bar. Also, need to find one, hopefully used.

This is what I use..

A slow steady cut Solid carbide tool works great...

Straight Flute Die Drills (USA)

http://www.pts-tools.com/cgi/CGP2LMXE

Drill Bits Carbide Straight Flute, Spade Drill, Inch Number Letter, Metric

.

Dan Stokes · #9 09-02-2013, 06:07 PM

Another option:

This often works well but each situation is different, your mileage may vary, etc.......

Get a nut of about the right size for the broken bolt. Weld it onto the stub (maybe just the end will be visible) of the broken bolt. WHILE IT'S STILL HOT back out the bolt. If you don't have access to welding gear have a mobile welder come out. It'll still be quicker and cheaper. Be sure the car is up high enough for the welder to get in there and make sure you have a reasonably clean and dry surface for him/her to work off of - it'll be cheaper.

Dan

Adriel · #10 09-02-2013, 07:35 PM

Thank you all for your help!

Quote:

Originally Posted by whunter

This is what I use..

A slow steady cut Solid carbide tool works great...

Straight Flute Die Drills (USA)

http://www.pts-tools.com/cgi/CGP2LMXE

Drill Bits Carbide Straight Flute, Spade Drill, Inch Number Letter, Metric

.

Hmmm, well trouble is, I spend $20 and another two hours, and the bit walks around and in the same place. All I have left is couple heater hoses I am hoping I can squeeze by, the master cylinder and booster, and maybe the vacuum lines. Then can undo the sway bar and get the old out. New will soon be on its way.

This has been somewhat of a positive situation, as the battery tray needs attention (caught just in time as major surface rust, but no holes), the body under the tray needs a good cleaning, and the sway bar mounts are hard as rocks. Yes, I could go many more miles with hard sway bar mounts, but will help improve the ride quality for which Mercedes is known for. Might even help with the passenger side sag.

Quote:

Originally Posted by Dan Stokes

Another option:

This often works well but each situation is different, your mileage may vary, etc.......

Get a nut of about the right size for the broken bolt. Weld it onto the stub (maybe just the end will be visible) of the broken bolt. WHILE IT'S STILL HOT back out the bolt. If you don't have access to welding gear have a mobile welder come out. It'll still be quicker and cheaper. Be sure the car is up high enough for the welder to get in there and make sure you have a reasonably clean and dry surface for him/her to work off of - it'll be cheaper.

Dan

Dan, that work when the bolt is proud. In this case, it is recessed a good 10mm into the sway bar. Though, will keep this in mind!

Stretch · #11 09-03-2013, 01:34 AM

I can't know for sure but I get the feeling that you've run the bit at too high a speed.

A cobalt drill bit is essentially a normal bit with a coating on it - if you drill with this at a high speed - allow it to get hot - the coating gets gone. You should operate these bits at a slow hand drill type of speed with lots of cutting oil / even WD40 (if you have to) to keep it cool.

Adriel · #12 09-03-2013, 01:40 AM

Quote:

Originally Posted by Stretch

I can't know for sure but I get the feeling that you've run the bit at too high a speed.

A cobalt drill bit is essentially a normal bit with a coating on it - if you drill with this at a high speed - allow it to get hot - the coating gets gone. You should operate these bits at a slow hand drill type of speed with lots of cutting oil / even WD40 (if you have to) to keep it cool.

Well, seems like a good possibility, as did some in the beginning but not now. I didn't use much "cutting" fluid and did go full speed a couple times, though most times less than a quarter trigger; figured low speed give more control. Does heat kill any drill bits? Might explain why my metric set went bad...

I use A.T.F. for cutting fluid now, as have a big bottle in Sandy Eggo so don't feel like buying another. I use A.T.F. from an antique oiling can, and this time has about a third of Kroil. The can lost its propellant, so jabbed a Phillips screw driver through it and poured some out.

I have most of the master cylinder out and just got to access the one nut, once that is off and the booster out of the way, can start in pulling the sway bar. I can fiddle for hours with no results or just get it done and over with. Say got about two hours at most in, and relaxed pace; hast makes waste! Figure even if it takes eight hours, way more enjoyable than in the wheel well going deaf and hurting! My arthritis no longer likes me being in a ball...

charmalu · #13 09-04-2013, 03:11 AM

As long as you are replacing the Sway Bar, it would be a good time to replace the 2 large Bushings on the Firewall. one under the Battery and one under the Brake booster.

Part# 123-323-12-85 or World pak# W0133-1807027, this is for the wagon 300TD.

Charlie

Stretch · #14 09-04-2013, 06:09 AM

Quote:

Originally Posted by Adriel

Well, seems like a good possibility, as did some in the beginning but not now. I didn't use much "cutting" fluid and did go full speed a couple times, though most times less than a quarter trigger; figured low speed give more control. Does heat kill any drill bits? Might explain why my metric set went bad...

Heat does indeed kill the cutting edge - have a look on youtube and watch some hardcore machine shop milling and drilling action - there will be a lot of coolant being sprayed on the working area (not that you need that much but probably a lot more than you used)

Adriel · #15 09-04-2013, 01:07 PM

Quote:

Originally Posted by charmalu

As long as you are replacing the Sway Bar, it would be a good time to replace the 2 large Bushings on the Firewall. one under the Battery and one under the Brake booster.

Part# 123-323-12-85 or World pak# W0133-1807027, this is for the wagon 300TD.

Charlie

Carlie, they are already ordered and are $4 each (Febi). Good point, and hope others do the same.

Quote:

Originally Posted by Stretch

Heat does indeed kill the cutting edge - have a look on youtube and watch some hardcore machine shop milling and drilling action - there will be a lot of coolant being sprayed on the working area (not that you need that much but probably a lot more than you used)

I know it can on machining, but didn't realize need to do it for ANY drilling. Believe it or not, I have some training in machining, just on the horizontal and vertical lathes. Made about a dozen oil pressure valves for air cooled Volkswagens and helped with a gear in a Jaguar window regulator. Man, that is a story!

Yesterday, made some progress. Got the booster out and the mounts un-done. Found out the manual is wrong, and have to remove the U.C.A. I just installed. Bummer... But, practice makes perfect!

Also found when the master cylinder was replaced, the brake fluid wasn't drained from the booster. That will shed a couple pounds!