Tackling a starter, need suggestions (and sympathy) - PeachParts Mercedes-Benz Forum

phidauex · #1 11-02-2005, 12:07 AM

Hi,

Around 2pm this afternoon I decided to finally do my 82' 300TD's starter replacement. My starter has been intermittantly whirring (without clicking), preventing a start. It gets worse as the weather gets cold, so I'm heading it off at the pass and changing it while the weather is decent (at least, thats the theory).

After a huge struggle that is basically a miniature version of what you are about to read about the top bolt, I was able to get the lower bolt on the starter loose, but now the upper bolt is giving me hell (of course).

My first tactic was to connect my 3/8" 10mm allen socket to a universal joint, then about 18" of extensions, which I fed up alongside the transmission pan. To this I connected a breaker bar. The problem was that even if I got the socket seated well, the socket would pop out before the bolt turned. Now, in its defense, it would pop out while I was pulling incredibly hard, as hard as I could pull.

The next tactic was to improve my socket by making a new one. I cut a piece from a 10mm allen wrench, and slipped it into a 10mm impact socket. It would let me pull a little harder, but would still eventually slip out.

To get some more torque, I started using my pneumatic impact wrench, which puts out a modest 250ft/pounds of torque. Unfortunately, I could hammer away all I wanted, and the bolt would not loosen.

Then I tried the 'from the top' method. I removed the aircleaner assembly, the battery and tray, and the heat shield that is in the way. From here, I could get small wrenches in, and was able to do things like insert the 10mm allen 'nub' I had made into the bolt, then grab it with a 10mm box wrench or something. Unfortunately, pulling as hard as I could from underneath with a breaker bar meant that getting sufficient torque with a short wrench was not going to happen. The space is still too tight to get my 1/2" breaker bar in from above.

Then I went to a store, and picked up a 500 ft/pound impact wrench.

More attempts from underneath, and no luck. I could get the socket to stay in the bolt, but nothing would move the bolt.

Went to more extreme methods, and drilled a big hole in the firewall. Now I've got a straight shot to the bolt, but STILL can't get it to budge, with either breaker bar or impact wrench. I'm worried that my compressor can't put out the full CFM necessary for the new wrench, so I'm half tempted to take the car to one of the gas stations with free air, quickly remove their tire chuck and attach a quick release, and put on my impact wrench, and see if I can break the bolt loose there. (I could tighten the lower bolt again, just enough to hold things in place, start the car, take it to the station, break loose the top bolt, and then gently retighten, restart, drive home, and then remove both bolts). But of course, there is no guarantee I could do it, even with more CFM...

All this time I've been squirting it with PBlaster and intermittantly applying heat with a MAPP torch, as well.

At this point I'm running out of ideas, and I've been tackling this bolt for over 8 hours. I'm filthy as sin itself, and in dire need of a beer and hot meal, but I'm not happy aboutthe prospect of ending the night in defeat. Anyone got any great ideas?

peace,
sam

Brian Carlton · #2 11-02-2005, 12:17 AM

I struggled with that cap screw myself. With a 1/2" breaker bar (18") and all of my strength, I could not break it loose while working from the back of the transmission, using extensions. I used 1/2" extensions with an adaptor for the 3/8" bit on the end.

So, I got a piece of pipe to fit over the breaker bar that was about 24" length and there was just enough angle to get the contraption up in there and torqued enough to crack the bolt loose. When it let go I though I was a goner. There was a crack that sounded like something fractured. But, the bolt had budged and from then on it was downhill.

You need a 24" stiff pipe (1.5" diameter is nice) and just about all the strength you have. While doing this, you must make absolutely sure that the socket bit does not slip out of the socket head on the cap screw. I can't recall, but I probably used the universal in the set of extensions to be sure that the bit went squarely into the screw.

I'm not a fan of the impact wrench. Too much localized force on the inside of the screw. The chances of rounding it off are very high. You don't even want to think about the consequences of this.

It's a difficult and miserable job. You have my sympathy. In my case, life was much easier after the screws were removed because I did the job with the manifolds off the right side of the engine.

phidauex · #3 11-02-2005, 12:46 AM

Quote:

Originally Posted by Brian Carlton

So, I got a piece of pipe to fit over the breaker bar that was about 24" length and there was just enough angle to get the contraption up in there and torqued enough to crack the bolt loose. When it let go I though I was a goner. There was a crack that sounded like something fractured. But, the bolt had budged and from then on it was downhill.

Well, I made another heroic attempt with the breaker bar, this time with a goodly piece of pipe over the end to give me a little more length. I seated the allen socket as securely as I could, used a universal to keep it straight, braced the extensions against the firewall, and pulled like heck. Like you, I heard a loud 'pop', but unlike you, it was the sound of the socket stripping the bolt, instead of the bolt loosening. Delightful.

There is still some usable grip inside the bolt head, but I'm done with it. I can't think of anything within my means that will make it better instead of worse. I suppose I'll just bolt the bottom back together, reassemble the topside, and then just hope the starter doesn't get any more intermittant than it is now.

Man, what a day.

Theoretically, if I were going to proceed with a partially stripped bolt head, what the heck would I do? Get someone to mig weld a big bolt head onto the cap? Pull the engine? Hammer a slightly oversize allen into the hole?

Man, I hate situations like this..

peace,
sam

RAYMOND485 · #4 11-02-2005, 01:47 AM

1984 300d Turbo
Lower The Trans 2-3 In. 2 Ft Ext To 10 Mm Socket Tap The End Into
The Top Bolt Remove The Four Trans Mount Bolts And Two Bolts
For Drive Shaft. Use Small Jack To Hold Up Trans Use A 10 In 2 By 4
Across Jack To Pan, Use 2 Ft Breaker Bar Use Jack To Move Breaker
Bar, It Will Pop. Diy Or Use You Foot On The Car Frame AND PULL ALSO
USE A FLEX EXT ON END OF SOCKET GET THEM AT ANY AUTO STORE
2-6 IN REMOVE GROUND ON BATTERY USE 17 MM SOCKET ON WIRE TO
STARTER, TURN FR WHEELS TO FULL RIGHT

#5 11-02-2005, 02:42 AM

Quote:

Originally Posted by phidauex

I'm worried that my compressor can't put out the full CFM necessary for the new wrench, so I'm half tempted to take the car to one of the gas stations with free air, quickly remove their tire chuck and attach a quick release, and put on my impact wrench, and see if I can break the bolt loose there.

Don't bother with the station tire compressor. It's just an oversized electric bicycle pump. It won't have enough CFM's to spin a wind wheel.

Drilling a hole in the firewall is cheating (But it's most likely the way I'd do it.

)

Pete Burton · #6 11-02-2005, 08:18 AM

Seriously, I'd MIG a good quality nut onto it. Drill out the inside of the nut so it just slips over the bolt head and chamfer that hole on the outside so the MIG gets good penetration. Make sure beforehand that nut will have a snug fit on the socket you will use.

SD Blue · #7 11-02-2005, 10:32 AM

Great suggestions. Sometimes a new, higher quality hex driver bit works on rounded out situations. You will be surprised at the variance in actual size.

kerry · #8 11-02-2005, 10:41 AM

If your access hole is big enough, you may be able to cut off the head of the bolt with a Dremel tool.

By the way, when I replaced the starter on my 77 I used one universal joint, about 3' of extensions and a 3' breaker bar. I did not lower the transmission. It took all my muscle on the 3' bar and it was awkward getting it in the right position because there's only so much turning arc when the car is just jacked up about 18". Why are those bolts so tight?

sailor15015 · #9 11-02-2005, 10:47 AM

I just had my starter replaced on my '85 300D. Like you, I got the bottom bolt loose but could not for the life of me figure out how to get that darned top bolt off. I tried extensions and universal drives to no avail. I finally took it to a shop a coworker knew of and they finally got it off. To their advantage they had a lift so the mechanic could stand under there and get a better angle on it while I was just lying on my back. I he used a universal drive, about two feet of extension, and about two feet of cheater bar. The sight of every mechanic in the shop standing under your car and shaking their head is never a good sign. He finally got it out, with that gut-wrenching "bang!" of the bolt breaking loose. They only charged me $90 for the labor, too. To me it was well worth it after my failed attempts to get the darn thing out. Sorry to hear about the stripped bolt. Its frustrating to try to fix something and only wind up making it worse. Don't worry. It'll work out. There are plenty of experienced mechanics here who I'm sure have dealt with something like this before.

#10 11-02-2005, 11:03 AM

For what it's worth, I had my mechanic replace my 300D starter. I watched him remove the upper bolt with the car on a lift. He has what looks like an extension about 3 feet long that is designed to flex and provide some instant torque (some Snap-on tool that costs $$$). With the rear tranny mount loosened, he was able to get a straight shot at the bolt head. Then, using a breaker bar, he flexed the extension a couple of times and gave it one good pull. The bolt broke loose on the first try. I never would have gotten it loose without a lift and the proper tools.

Ralph69220d · #11 11-02-2005, 11:04 AM

I may be mistaken, but if the starter is "whirring", that sounds more like the bendix drive is bad. Can the bendix be removed easily on your starter without the removing the whole starter/bendix assembly?

barry123400 · #12 11-02-2005, 02:43 PM

At this stage you should probably consider the ideal of welding a nut on. The heat traveling up the bolt should help to free it to some extent. The hex is already pretty well stripped I believe you mentioned. The weld needs to be pretty good and more than just a spot or two inside that nut. I would not cut the head off the bolt as the remaining stud may be really still seized pretty solid. You could also weld a nut on that stud as well I guess but the weld area will be smaller. Again the travelling heat is going to help a lot to loosen it in my opinion. Also go pretty hot when welding the nut on. You want a lot of heat transfer up that bolt plus of course it aids penetration of the weld. Some things just turn into a mysery it seems. The starter does need changed one way or another from your description.

dmorrison · #13 11-02-2005, 02:47 PM

Had difficulty removing the upper bolt on the 560SL. Very frustrating. Talked to the mechanics at the dealer.
Here is how they do it.

Use your Allen socket. Make sure you clean the bolt head receiver.
Go out and buy a 1/2 inch wobble extension.

http://froogle.google.com/froogle_cluster?btnG=Search+Froogle&hl=en&oid=5328758093738202722&pid=4833505089111547289&q=wobble+extension&scoring=p

Either as long as you can find or long enough so you can attach another, non wobble extension.
Raise the car as high as you can. On 4 tall jack stand or best, on a lift.
the wobble extension will allow a transfer of the torque that a universal will not allow.
Get a very long breaker bar or and pipe extension to the breaker bar you have to. With about 36 inches of extension, you can really get on the breaker bar/pipe extension setup.
This is how the dealer does it. Use ONLY a wobble extension for the slight turn at the starter bolt. Then all other extensions should be straight.
You can use a wobble adapter (harbor freight and sears sells them)
The mechanics recommended 1/2 inch drive extensions ONLY. He said the 3/8 inch drive will flex and not allow the torque to transfer.

Dave

PS I did not remove the starter on the SL. I did some more trouble shooting and realized it was not a starter problem.

#14 11-02-2005, 03:46 PM

Not sure if anyone specifcally mentioned this but you might as well not bother using an impact wrench unless you can get the socket and the wrench together (ie...no extention)

All the extention does is torque around and takes up the "bang" that the impact normally would have when directly coupled.

I couldn't get this one bolt off...seemed like the impact should do it. Dad mentioned removing the 4inch extention I was using so I took it off...zapped the bolt off no problems.

For future reference...impacts and extentions don't give you your full loosening/tightning force at the bolt...

phidauex · #15 11-02-2005, 04:20 PM

Excellent suggestions, everyone. I've got a lot to think about now... At least I'm fortunate in that the starter still works most of the time (this was supposed to be 'preventative' maintainence), so I can still drive around as I figure out a solution.

I did try removing just the solenoid, but that wasn't going to happen. The little rusted phillips head screws holding it on weren't going anywhere, and the location was equally bad.

Today I think I will buy some rubber plugs for my firewall holes, and think about things. I need to decide whether I'll go at it again myself, or whether I'll cave and take it to a mechanic. Do mechanics get pissy if you just ask them to do one little thing like that (like a chef if you asked them to just make one part of your meal so you could go home and do the rest), or are they usually OK with taking on a quick 'labor only' job for a stuck DIYer?

I've got a friend with a modest MIG welder, and I'm an OK welder myself. He's better, but doesn't have much automotive experience. I suppose I could get a big ole bolt (grade 5 maybe?) and then drill a hole through it (assuming my simple titanium-nitride coated bits could make it through hardened steel, I do have a drill press however), and then weld it over the cap screw. I'd need to open the firewall hole up from a 3/4" hole to a larger 'access port', but I suppose as long as I've got the welder around, I could just weld the cut-out piece back on again, with a few thin strips as 'bandaids'.

Before I did that, it would probably be worth a few good wacks with a center punch and then one last shot with a new allen socket.

Anyway, plenty to mull over.. The impact wrench / extension issue is something I hadn't really thought about... I do remember thinking to myself "damn, these 3/8" extensions are like little springs". With 18" of extensions, I could get almost a quarter turn of pure twist using the breaker bar. Unfortunately, my half inch extensions weren't going to make it alongside the transmission pan. I do love my impact wrench, but it wasn't helping much for this job (not that any of my tools really helped that much).

Again, thanks a lot, folks, I like it here because you not only have good ideas, but you feel my pain as well.

peace,
sam