by ramm440, October 27, 2010
I have a 1999 1.8 litre Corolla that has had the Serentine belt tensioner bolt break off in the block. From reading other postings on the net this seems to be a common SOB.
I am afraid to use a right angle drill and am considering removing the timing chain cover to get a good straight shot at it. Can anyone tell me the main parts to be removed to get the timing chain cover off - Does the valve cover have to be removed etc??
Thanks Robert
Yes ,valve cover , drive belt, alternator, power steering pump , pass side engine mount,water pump( drain coolent), crank pulley, crankshaft position sensor,timing chain tensioner,pan bolt into timing chain cover. Yes lots of work. I would buy a manual before tearing this far into the engine.
I am still considering a right angle drill - been soaking in liquid wrench overnight - Ever had this happen? Does timing chain tensioner need to be removed? (I had the serpentine belt tensioner bolt broke off in the block.) I have never touched the bolt as the tensioner has a aluminum cast nut that is used to release pressure when changing the belt. Here is a link to others experiencing the same problem - thx
http://www.9thgencorolla.com/forum/showthread.php?t=105758
Yes ,valve cover , drive belt, alternator, power steering pump , pass side engine mount,water pump( drain coolent), crank pulley, crankshaft position sensor,timing chain tensioner,pan bolt into timing chain cover. Yes lots of work. I would buy a manual before tearing this far into the engine.
Only if you pull the timing cover, its not like the earlier model corollas with a timing belt( plastic cover ,dry no oil) . The cover is metal, sealed so oil will not leak out( timing chain wet with engine oil) oil .
Yes you will have to take out the tensioner before you remove the cover.
Depending on where the bolt broke ( how much sticks out) It may or may not be worth taking off the cover .The cover is 5/8" thick where the bolt goes through.
I have heard of these breaking before , but dont really understand why.
If the bolt broke while trying to remove it ( rusted in hole) it would be a bear to get out.
It sounds like it broke from other stresses though, so the broken peice should be easy to remove( if there is no corrosion).
Just dont break an easy out off in the bolt( seen it many times) or you will never get it out.
If enough sticks out (cover on or off) ,you could slot the end with a dremal and use a screw drive to remove it or vice gripes if alot sticks out . I have used stacks( heat shrinked or glued together) of small neo magnets to remove loose broken bolts that were flush with the surface.
If you have to drill out the center of the bolt, punch the center first and then use a small pilot drill and plenty of oil to keep the bit going straight. Then go larger slowly until you can colapse the bolt and remove it. This only needs to be done if the bolt is frozen in the hole.
If the bolt is broken off flush or down in the hole but is loose ( turnable) then you can drill a hole large enough for your easy out( use the largest one that will fit) and get it out that way. Or use the neo magnet trick , the broken end of the bolt has to be flat and you need a good stack ( mine has about 30 magnets stacked together) .
The biggest variable, and what determines how you remove the bolt ( what method ) is how tight the bolt is.
The bad part with this particular bolt is that it threads into the block a long way and the access is poor.
I really appreciate your thoughts - The bolt broke off due to stress from the tensioner going bad and it has never been loosened or tightened except by Toyota. I thought that it threaded into the timing cover not the block. Am I wrong? It is recessed in about 1/4 inch. It appears as though this type of bolt has a tit on the threaded end and bottoms out upon assembly.
Please send anymore you know about my questions
Thx
Robert
No it threads into the block.
It does not bottom out in the block, but pinches the bearing in the tensioner arm.
Thats good for you because once the head portion of the bolt broke off there should be no more tension on the peice of bolt left behind ( should be loose).
It should be loose unless the bolt damaged the threads.
If it is really only 1/4 " inside the cover and you cant get it out without removing the cover , then at least you will have a 1/4"( cover is 5/8 thick) or so to grab onto with vice grips or to slot for a screwdriver once you get the cover off.
Been monkeying around with it again -
I was putting liquid wrench around it - now I am using freeze off penetrating oil - There is definitely 1/4" in on one side and a little more like 7/16 distance from the mounting surface in to edge of whats left of a bolt. Like you said maybe vicegrips will work if I have to pull the cover. I put a fuel line into the bolt hole that fit snug and shot penetrating lube into it to let it soak another night around the SOB thats left. I am using very small screw drivers trying to get it to turn but no luck yet. If I don't get some results soon I think I'll attempt pulling the cover this weekend. Any more ideas on how to turn it?
I don't have a manual but have already removed the Motor mount, the windshield wash bottle, the power steering resevoir (to the side), and other small junk in my way. What type of puller works best on the for crank pulley? Does the crankshaft sensor go on/off only one way? I can handle the other stuff just want make sure I don't put the sensor back on wrong or bend a pulley. R and R valve cover , drive belt, alternator, power steering pump , pass side engine mount,water pump( drain coolant) are manageable.
If I accomplish this I will be checking the tensioner alot for play.
Thx
Robert
Crank pulley will usually come off without a puller , just wiggle it off, couple light taps with plastic hammer.
Crank position sensor only goes on one way.
Manuals are cheap and it is one of the best tools you can have.
Once your cover is off ,if the bolt is not sticking out, you can use a punch or chisle and hammer to turn the bolt( if there is enough room). If it is easy to turn ,the magnet trick really does work ,especially in a tight spot
Thanks Bent,
I just was pissed at the tensioner bolt causing me all this work and it really wasn't that bad. I pulled the timing chain cover today and easily removed the broken bolt with plyers.
I bought a new valve cover gasket and crank seal, spark plugs, rtv sealant and Gates tensioner. I still need to buy a new tensioner bolt @ Toyota maybe its $7.50 and special order. Is that best or a grade 8 or higher at a hardware store? The Toyota bolt has a tit on the end with no threads - Does it need to be the same OEM bolt?
Its kind of weird how the Timing chain tensioner gets installed with the little hook latched and in the compressed position. Is that correct?
I hope this helps someone else as you greatly helped me - I owe you a cold beer!!
I will take some pics and try to post
Thx
Robert
Thanks Bent,That timing chain tensioner will get bumped and the hook will disengage on its own. If you wiggle the crank pulley to turn the motor over, you can hear the tensioner "pop" out. If you don't hear that - you can try and release it manually, should be able to get to it with the valvecover off, be just enough room.
I just was pissed at the tensioner bolt causing me all this work and it really wasn't that bad. I pulled the timing chain cover today and easily removed the broken bolt with plyers.
Its kind of weird how the Timing chain tensioner gets installed with the little hook latched and in the compressed position. Is that correct?
I hope this helps someone else as you greatly helped me - I owe you a cold beer!!
Thx
Robert
Grade 8 bolts do have much higher tension and shear strength than lesser bolts, but they are also more brittle and can crack on impact. Where a softer bolt would yield slightly but not break. Plus the actual strength will also be dictated by where the bolt is threaded into, this case the block. If you had to buy a stronger bolt, I'd go with a Grade 5 - ask the dealership what Grade their bolt is.
That timing chain tensioner will get bumped and the hook will disengage on its own. If you wiggle the crank pulley to turn the motor over, you can hear the tensioner "pop" out. If you don't hear that - you can try and release it manually, should be able to get to it with the valvecover off, be just enough room.Thanks Bent,
I just was pissed at the tensioner bolt causing me all this work and it really wasn't that bad. I pulled the timing chain cover today and easily removed the broken bolt with plyers.
Its kind of weird how the Timing chain tensioner gets installed with the little hook latched and in the compressed position. Is that correct?
I hope this helps someone else as you greatly helped me - I owe you a cold beer!!
Thx
Robert
Grade 8 bolts do have much higher tension and shear strength than lesser bolts, but they are also more brittle and can crack on impact. Where a softer bolt would yield slightly but not break. Plus the actual strength will also be dictated by where the bolt is threaded into, this case the block. If you had to buy a stronger bolt, I'd go with a Grade 5 - ask the dealership what Grade their bolt is.
Grade 8 bolts are SAE. You can tell by the hash marks on the head of the bolt..
Metric bolts have numbers on the head.
Toyota Uses metric bolt.
Also do not OD with RTV....
Had the exact same problem, with the tensioner bolt breaking off in the block. Removed the valve cover, alternator, r - motor mount, water and power steering pumps, crank shaft pully and position sensor, timing chain tensioner and cover. Enough of the broken bolt was sticking out and it unscrewed by hand.
Thanks for the advice, because I was thinking the motor had to be pulled.
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