Tips for removing water pump pulley?

Hey guys, I’m in the middle of (and probably going to be over my head in) the process of changing the timing belt on a 1996 Mercury Mystique 2.0L I4. I haven’t gotten too far yet, because I’m stuck on how to get the water pump pulley off. It’s got four tiny 8mm bolts attaching the pulley to the pump, and it’s driven by the serpentine belt. I need to remove it because it blocks access to the timing belt, and anyway I want to replace the water pump while I’m in there.

I can get a box-end wrench on it (there’s not much space, so even my 1/4"-drive socket won’t fit), and slip a pipe over it to get leverage, but the problem I’m sure you’ve all encountered is that the pulley turns instead of the bolt! I’ve gotten my roommate to hold a breaker bar on the crankshaft pulley so that the serpentine belt doesn’t move, but there’s not enough friction to stop the pulley moving underneath the belt.

I was wondering if you guys had any time-tested advice for getting the damn things off. I’ve loosened two but the other two are stuck, and a soaking in WD-40 hasn’t helped (though it probably has helped the pulley slip on the belt). I’m replacing the serpentine belt anyway so I don’t mind damaging it if necessary. I’m starting to round out the bolts now, so I figured I’d ask you guys before I do too much damage and need a professional.



What I do is take a screwdriver or a pry bar and place it between the heads of two bolts so it prevents the water pump from turning.


You are going to replace the belt, so damage will not be a concern.
I have used a small 6 inch mill file to slip between the belt and the pulley. It will take a little slack out of the belt and have the little grip on the pulley
Put your wrench on the bolt and turn the pulley while you let the file get pulled in between the pulley and belt.


You may have already gotten through this problem but another method is to roll up an old rag very tightly and wedge it between the belt and pulley so any forced movement will try to cram the rag in between the two.

Awesome, thanks for the advice. I’m gonna try them out in what I see as decreasing order of the change of messing something up; that is, the rag, then the screwdriver between the bolts, and then the file. I wish they’d just put a bolt head on the pulley so I could use a socket to stop it turning!

Another thought . . .

Assuming this engine has an automatic belt tensioner, use your ratchet to put extra tension on the belt, while you loosen the bolts

That’s not a bad idea! It does have an automatic tensioner – I’ll just have to wait til my room mates get back to try it out. The rag didn’t work, sadly, and I couldn’t find a tool the right shape to jimmy between the bolts to hold the pulley in place. I’m trying now to find one of those rubber jar-openers, and then pull it between the pulley and the belt to apply some friction.

AHAHAHA I got it! It took me close to two hours, including a lunch break, but by god I got those little bastards off. The tool: a latex balloon, pulled in between the belt and the pulley by turning the crankshaft. It made enough friction to stop the pulley from turning.

Thanks for the help guys – you all gave me the idea of putting something in between the pulley and belt, and the thing ended up being the most unlikely mechanic’s tool I’ve ever seen.

Now to get back to work!


Is the serpentine belt still on?

If not, put it back on, and use that idea I gave you

Funny how sometimes the oddest things will solve a problem.

I had one of those “Latex balloons” in my wallet for the longest time. You couldn’t even read the label any more.

What can I say…it was a dry spell!!!


Where do you guys get replacement bolts? I rounded some of these pretty good and I’d like to pick up some extras. Do auto parts stores usually sell bolts, or should I try a regular hardware store?

@Yosemite Might as well use it for something, then! Just gotta make sure it’s not lubricated, otherwise it won’t hold the pulley

You can try the auto parts for the bolts, but a hardware store will have them too. I’d buy grade 5 bolts that are a little harder alloy. A regular bolt may break when you try to get it off next time.


Yeah, these are marked 10.9 so I’ll try and get hardened bolts that match the spec (I think 10.9 is the metric equivalent of 8?)

If you have an ACE hardware store nearby, that’s the source for hardware.

I had a Chevy Trail Blazer come in with a missing caliper bolt. I removed the other caliper bolt and went to the ACE store.

To my surprise, they matched me up with the same exact bolt!


My local hardware store usually has the proper replacement bolts when I have this round-off problem. There’s such an assortment of metric/non metric, fine, coarse thread, strength ratings, etc, you sort of need a Ph.D. or equivalent in bolt nomenclature to get the right ones. And a lot of patience to find them. It used to be the staff there could help you find the one you needed if you brought in the old one, but these days the staff usually barely knows what a bolt is.

fyi to the OP, on my Corolla it’s not possible to remove the water pump pulley without first doing a bunch of stuff, including removing the engine mount and jacking up the engine a bit. I’m wondering if the OP might be making the job tougher by not doing some of the preliminary moving-stuff-around first. Since the timing belt was part of the job, that all had to be done eventually anyway. Maybe it was a work sequencing issue that made this so difficult.

I’ve never had difficulty removing pulley bolts on accessories. Sometimes I had to use the normal method, tighten the belt a little so the pulley wouldn’t move. The only pulley bolt I encountered that was difficult to remove was the center crankshaft pulley bolt. I had to make a tool out of some plywood that would hold the pulley still while I turned the bolt with a socket. That particular pulley design has two little holes in it, which I assume if for that purpose. Toyota must have a special pin-tool to do the job of my plywood gizmo.

I had pulled off a bunch of stuff, including the motor mount, coolant reservoir, air plenum, etc. There’s just not much clearance in there; the pulley’s right up against the side of the engine compartment. I think these bolts were such a pain mostly because they haven’t been removed in 17 years!

Thanks for the advice about the hardware store – I guess I’ll bring an old bolt and the new water pump and just try stuff out til it fits! Unless there’s a helpful person around who knows what they’re doing better than I do (which sets the bar pretty low, honestly).

Um @Yosemite that may be why your wife is burning your supper so much.

Those bolts may have had thread locker on them which made them hard to loosen up. Take a look and see if there is any blue or red residue on them. On my GMs, I always used the blue thread locker on the pump bolts on reassembly so they didn’t loosen up.

@Bluegill … on my Corolla with a transverse mounted 4-banger the water pump pulley is right up against the engine compartment wall too. I’ve never had to change-out the water pump yet, but somehow the water pump pulley is involved with changing the timing belt, but I forget why, did the timing belt job several years ago. I think this water pump pulley clearance problem must be a common problem in transverse mounted engines. I have no such problem when changing the water pump on my longitudinally mounted Ford truck for example, that’s a relatively easy job compared to the same on the Corolla.

On the Corolla what I have to do is remove the front mount and 2-3 add’l mounts underneath which hold the transmission down onto it’s chassis support beam, then I can jack up the passenger side of the engine/transmission about an inch, maybe 2, enough to access the bolts on the water pump pulley. I don’t have to monkey with the left engine mount, it has enough give to allow a 2 inch jack up apparently.

One more thing that might prove helpful to you, when I did my timing belt job I had a problem with rounding some bolts too, just not the water pump ones. I discovered the sockets I was using was the source of the problem. Over time the socket had deformed, enough to round over any tough to loosen bolt. I took the affected sockets back to Sears and showed them the problem – they are Craftsman so are lifetime guaranteed – and Sears gave me new replacements.

Now that I think about it, another problem I had with that job is my sockets are 12 point rather than 6. I’ve since got some 6 points, which are less likely to round off bolts. I guess the reason they make 12 point sockets is that it is easier to get the socket on the bolt, there’s 12 ways to do it rather than 6, but 12 point sockets are more likely to round off the bolt than 6. Anyway, that’s according to what the experts here say.

Best of luck to you. Very few people work on their own car at all, let alone attempt a timing belt job, so good for you for giving it a go. It’s certainly possible for a DIY’er to change a timing belt, but that’s one job especially where it would be very helpful to watch someone else who knows how to do it, do it first.

@GeorgeSanJose I do like a longitudinally mounted engine – my step-dad has an old Toyota pickup, and I swear you could store a few suitcases in the empty space in that engine compartment. This car is pretty cramped – the list of stuff you have to take off to change the water pump is pretty lengthy (including the power steering pump, which I’m wrestling to put back on right now). I might try jacking up the engine a little when I put the water pump pulley back on, though – I think that would actually help a lot. It looks like the left side motor mount is on a little rubber footing that should allow enough play to lift it a little.

Thanks for the words of encouragement. I like to maintain my own stuff, and learn how it works. However, this 2.9 hour job is going to end up taking me three days, so I’m starting to doubt the wisdom of it. I’m new to my town and haven’t met any mechanically-inclined types yet, so it’s me, the Haynes manual, and Youtube videos working on this one.

Mostly it’s a way for me to justify buying more tools. I bought a floor jack and an impact driver just for this job, but now I’ve got them in the garage for next job (which will be struts, I think).

It’s kind of a bummer though, now that I’ve taken off the timing belt, that everything looks like it’s in really good shape. No wear that I can see on the idler, and the belt itself looks brand new. I know it hasn’t ever been changed, though, and 17 years is a little long to run the thing – I just wonder how much life it had left in it!