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Calling All Experts! I Need Help!


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Last night I went to pick up my SC300 from the mechanic where I was getting a new timing belt thrown on. Apparently they had been wrestling with the harmonic balance bolt all day and were unable to get it free. Supposedly its supposed to take about 200 ft/lbs of torque, but they were unsuccessful with 600 ft/lbs!!

My mechanic had spent the day on the phone with Toyota dealership here in town and the Lexus dealership in Houston. In Houston he found a guy that has been working with Lexus since '90 and said that he had done over 400 timing belt changes on the SC. Over 13 years and 400 cars only on THREE had he encountered this problem. Some issue with the aluminum bolt threads corroding and become severly locked in place.

They tried stacking another battery or something with the starter and locking the bolt in place, no luck. They tried 600 ft/lbs of torque, no luck. They CAN try the larger machine used on 18-wheelers to achieve 1000 ft/lbs but they would need to remove the compressor and a couple other things to get clearance and who knows what would happen if the bolt still didnt budge.

Sorry for the long post but I just wanted to give you guys all the information I can to try to get some good advice. If someone has some kind of wonder cure that would, of course, be incredible. Otherwise I guess I just need a worse case scenario. If I give them the go ahead to try the 1000 ft/lbs what could happen? If the bolt still doesnt free up how much damage am I looking at? I assume I could screw up the cam shaft and other things. I basically need enough information to make a wise decision. Ive still got around 10,000 miles left on the timing belt so Ive got some time to figure this out.

Thanks a lot

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My research this morning has only yielded one little tidbit of information:

Question: 1994 Toyota 4Runner v6 mileage: 151k. Took my 4 runner to the Toyota dealer to change the timing belt. It was changed before at 65k it now has 151k. They ran into a problem. There is a pulley, which is bolted onto the crankshaft. They turn the bolt 3 times and said it should have broken free and been able to hand turn. The said that they can try to cut the bolt off and remove the pulley to see what's going on behind there. But, they said I would most likely need a new engine bottom. Roughly $3-5k job. Does this sound right?

Answer: It sounds as if the threads that hold the bolt to the bottom pulley on the crankshaft are stripped. When the belt was changed at 65,000 miles it may have been over-tightened, which could damage the threads. What we would do is remove the radiator and the grill to gain clear access to the front of the engine. Then we'd remove the bolt in question. If it broke off, we would drill it out and tap the end of the crankshaft. If the threads were damaged beyond repair, we would drill and tap it out to the next size larger. This would cost considerably less that $3000.00, more like a couple hundred dollars for the extra work.

Is something like this feasible on my engine and preferrable to trying to force the bolt loose?

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Meddle, I got your pm this morning but was unable to reply. This happens on occassion on bolts especially on cars. I had a retainer clip degrade and fuse my driver side brake rotor cap on a honda so that the rotor was impossible to remove even after 3,000 lbs. of force from a hydraulic spreader. :rolleyes: The whole assembly had to be removed and soaked over night in a corrosive goo to get the offending pieces separated. Anyways - onward.

So to your situation - the cause mentioned above in your quote is most likely the situation. I imagine they did try to cold crank the motor with a wrench on the bolt? Did they try some type of thread penetration material such as pv blaster or the like? It will have to soak over night at the least and of course, we aren't going to pull the motor and the like just to get a pulley out. Have no fear, you do not need a new bottom end. That is rather drastic. Patience will take care of this situation. If your shop is not cooperative, have them put everything back and move on.

Okay, so say the thread penetrator is not working. Well then they are going to have to take a die grinder or something to the bolt. You may want to be prepared to get another pully too just in case. Once that offending nusiance is removed the bolt stud can be drilled out by a patient indivial willing to work in that limited area. It would be easiest done on a lift. After the stud is removed the threads should be chased at the least by a corresponding tap die. Then get a new grade 8 bolt of the right size, and possibly new pulley :unsure: if the die grinder guy slipped or something :blink: , use some anti sieze on the threads of the bolt before tightening to the correct torque by hand with a torque wrench - don't let them use those pesky impact wrenches they like so much as that is porbably how this happened in the first place ;) . That should do it. Just a little patience and :magic: it should be just fine.

Good luck - I'm sure all will turn out fine.

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Haha! Im in Dallas right now! I bought my car here from Sunbelt Motorcars, and took it home for the weekend to get the timing belt thrown on (which was obviously more of a nuisance than I had assumed). Who do you work for? I called Davenport Lexus and they said "nah we can do it, dont worry about it" and they gave me a gaurantee that if they were unable to free the bolt I would not have to pay for the labor. They also said that they have NEVER seen a timing belt actually fail on an SC300 (I doubt that) but I hope this means that I should be just fine taking my car back up to Dallas for the weekend to get this fixed.

Davenport quoted me $900 for the full timing belt job. Which includes of course the belt, water pump, cam seals and whatever else a dealership would usually do.

I read my post and realized it was a little confusing as to why my car wasnt here with me in Dallas. Im working here for a couple months, and Im from College Station. Ill be here off and on this summer so bringing the car up to Dallas is not a problem.

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A car savy friend of mine said to carefully take a torch to the bolt to heat it up. Once its nice and hot it should come right out....

That is what we do here at the factory when bolts sieze up. But I get nervous with a torch around my pride and joy. So JPI, no input on how to get frozen crank pulley bolt out? Eazy outs won't work. Unless you got a reall good set.

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Cmon guys this is a public lexus enthusiasts forum. No reason to hide your SECRET methods for solving a problem. In all likelihood the members of this forum are not in the same area of the country as each other, so your business will not be damaged.

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