The Valley of broken bolts...my story of water pump replacement

[BigBenb84]

I was hoping for one of those easy VOD jobs replacing the water pump and peripherals but bolts have sheared left and right or seized and I can't get them out or loose. I've come here seeking ideas. I was trying to get this done by DCS but it's looking grim.

1. 3 of the 4 intake manifold bolt heads broke off. I was trying to be careful but they broke like they were made of warm butter (why are they such tiny bolts?!) There is only like 2mm or less poking from the surface
What I have tried: drilling down the center of 2 of them and using an extractor (cone shaped with reverse threads) but the bolt won't budge. I also heated it with a torch for a minute but no luck. Been spraying PB blaster on them for a week now.

2. One bolt in the Y pipe sheared. Left side towards rear of the car. I did the same as 1, drilled hole and tried using extractor plus heat! no luck. Soaked in PB Blaster for a week too.

3. So when you get a new water pump you have to transfer the backside off your old pump to the new one. Well, the hex head screws that hold it on will not budge. I've tried PB Blaster and heat and even hitting the Allen screw with a mini sledge hammer to get it to break loose but it is not letting loose.

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[DMCMW Dave]

1. 3 of the 4 intake manifold bolt heads broke off. I was trying to be careful but they broke like they were made of warm butter (why are they such tiny bolts?!) There is only like 2mm or less poking from the surface
What I have tried: drilling down the center of 2 of them and using an extractor (cone shaped with reverse threads) but the bolt won't budge. I also heated it with a torch for a minute but no luck. Been spraying PB blaster on them for a week now.

2. One bolt in the Y pipe sheared. Left side towards rear of the car. I did the same as 1, drilled hole and tried using extractor plus heat! no luck. Soaked in PB Blaster for a week too.

3. So when you get a new water pump you have to transfer the backside off your old pump to the new one. Well, the hex head screws that hold it on will not budge. I've tried PB Blaster and heat and even hitting the Allen screw with a mini sledge hammer to get it to break loose but it is not letting loose.
]

I've found that PB blaster etc. is relatively worthless when aluminum is involved.

It's a delicate process. On the water pump, you'll probably need to buy new bolts. Cut the heads off the old ones to save the back. That's the fun part, they are hard to find and you really should not use standard hex head bolts there as the clearance to the back of the pump is too small. You either need allens (which I have never found) or the Volvo replacement that is a 12-point small head bolt. They are insanely expensive for what they are.

You might be able to slot the water pump body in line with each bolt to get it to cut loose, but this will be hard without damaging the back.

The other ones are probably going to have to be drilled out and time-serted (high class heli-coil). You may want to find someone experienced to do this as it's a difficult process and if it goes wrong you end up with holes into the water jacket of the head. The tricky part on the intake bolts is that they go in at a very odd angle, and if you miss or go too deep you will hit coolant.

There isn't much you can do to avoid this, other than striking the bolts before trying to loosen them in the hope that you can upset the rust. If yours twisted off that easy they were probably very rusted and were going to break no matter what. Try to find a machinist who as dealt with such things. It's a good talent to have but this is a dangerous place to learn it. Cost of failure is much higher than the cost of finding someone who has done it.

Another recommendation is to avoid like the plague even trying an EZ out (left-handed extractor). They will just break off in the hole you drilled in the bolt, and now you have a chunk of metal in there that is harder than the drill bit you have to get it out. EZ outs may be OK in wood but usually worthless in metal work. I can't say that I've ever had one work as advertised.

[BigBenb84]

Thanks Dave for the pointers. I guess I'll wind up cutting off the back pump bolts. As for the manifold bolts, I'll try drilling out those bolts a little more, maybe they'll break up. I've been googling and researching the Time-serts, pretty cool. Looks like I'd want the M7x1.00 kit? $76 bucks yikes. Comes with 5 serts, I need 4 (3 manifold and 1 Y-pipe).

[Mark D]

Yikes...This thread is not inspiring me with much confidence. I've got a VOD cleaning/water pump replacement in the near future but now I'm looking forward to it even less. I've put it off for several years now.

What was your motivation for replacing the water pump? Was it actually weeping coolant? or was there some other reason for needing to replace it?

My main motivation for wanting to dig into that area is to clean out any gunk that may be in the VOD and replace the few remaining original coolant hoses that are left on my car with new rubber. I've also got few remaining silicone vacuum hoses to install. My water pump is currently fine, but I figured while I was in there I'd replace it. The main issue is my fear of snaping off the intake and y pipe bolts.

[DMCMW Dave]

Thanks Dave for the pointers. I guess I'll wind up cutting off the back pump bolts. As for the manifold bolts, I'll try drilling out those bolts a little more, maybe they'll break up. I've been googling and researching the Time-serts, pretty cool. Looks like I'd want the M7x1.00 kit? $76 bucks yikes. Comes with 5 serts, I need 4 (3 manifold and 1 Y-pipe).

A trick on the manifold bolts is to put a screw in one of the good holes so you have some idea of the angle you are attempting to hit. Sometimes drilling them out with a left-handed drill bit will help too.

Wait until you try to buy the right bolts for the water pump back. I think they are close to $8 each from Volvo.

[BigBenb84]

What was your motivation for replacing the water pump? Was it actually weeping coolant? or was there some other reason for needing to replace it?

For the past few years the pump would weep a little here n there, also getting kinda noisy. I was living with it just driving locally but I wanted to take it to DCS, 750 miles each way, so I wanted it fixed.


A trick on the manifold bolts is to put a screw in one of the good holes so you have some idea of the angle you are attempting

Great minds, I actually did that tonight. Would this be the time-sert to get?: Amazon Time-sert M7x1.00 (http://www.amazon.com/TIME-SERT-Metric-Thread-Repair-1710/dp/B001ZS9VCY/ref=sr_1_1?s=automotive&ie=UTF8&qid=1401941438&sr=1-1&keywords=Time-sert+m7). Is that right the sert is only 10mm deep? That doesn't seem deep enough..

[Bitsyncmaster]

Great minds, I actually did that tonight. Would this be the time-sert to get?: Amazon Time-sert M7x1.00 (http://www.amazon.com/TIME-SERT-Metric-Thread-Repair-1710/dp/B001ZS9VCY/ref=sr_1_1?s=automotive&ie=UTF8&qid=1401941438&sr=1-1&keywords=Time-sert+m7). Is that right the sert is only 10mm deep? That doesn't seem deep enough..

From the photos, it does look like that insert has a solid bottom to it. Using a helicoil type insert there is no bottom so the longer bolts are fine.

[David T]

From the photos, it does look like that insert has a solid bottom to it. Using a helicoil type insert there is no bottom so the longer bolts are fine.

The only thing that seems to help is heat. You get the head cherry red once or twice and then try removing it. You can't get penetrating fluid where you need it to be and it is of little help anyway. Once the bolts are broken off Dave S's advice is about the best there is. The big problem is the bolt is hard and the aluminum is soft so it is very easy to get off the bolt and into the aluminum. Unless you are very patient and can stay centered you will probably have to oversize the hole and have to install a thread insert.

[DMCMW Dave]

From the photos, it does look like that insert has a solid bottom to it. Using a helicoil type insert there is no bottom so the longer bolts are fine.

Timeserts are open on the bottom. They are available in longer lengths.

[mluder]

I've had the most luck combining heat with penetrating oil. I heat the bolt until its red then hit it with penetrating oil - PB Blaster is my brand of choice though there was a recipe floating around made from brake fluid if I recall. Any way, the head causes the oil to get pulled up into the threads helping free things up a bit more. That was the only way I could get my exhaust crossover pipe free.

Cheers
Steven

[DMCMW Dave]

I've had the most luck combining heat with penetrating oil. ........ That was the only way I could get my exhaust crossover pipe free.


I've never had penetrating oil help at all in aluminum/steel bonds. There is no aluminum involved in crossover pipe joints.

The absolute worst is putting (dry) stainless fasteners into aluminum. You may as well weld your engine together.

[mluder]

I've never had penetrating oil help at all in aluminum/steel bonds. There is no aluminum involved in crossover pipe joints.

The absolute worst is putting (dry) stainless fasteners into aluminum. You may as well weld your engine together.

All true... I was thinking more technique rather than direct correlation. Still, you have way more experience than I do and I've been fortunate to have broken only one bolt. It was an exhaust manifold to engine so that was a steel on aluminum connection. I was able to get it out by drilling the center with a left hand thread bit and a bolt extractor. Again, I count myself extremely fortunate.

[David T]

All true... I was thinking more technique rather than direct correlation. Still, you have way more experience than I do and I've been fortunate to have broken only one bolt. It was an exhaust manifold to engine so that was a steel on aluminum connection. I was able to get it out by drilling the center with a left hand thread bit and a bolt extractor. Again, I count myself extremely fortunate.

Heat works the best with the exhaust hardware and especially steel on steel. It can't work if you break the bolts first before using heat. Be sure to use Never Seize when reassembling things. The nest person to take things apart again my be YOU! Learning how to use an Oxy-Acetalyne torch is a very handy skill. The equipment is not expensive and the skills are not difficult to learn, all it takes is practice. With it you can heat, heat treat, weld, braze, solder, and cut.

[BigBenb84]

Would there be any thing against going from M7 to an M8 sized hole? I understand don't go deeper, but 1 mm larger? M8 is much more common then M7 and I might have to go that big to get out what is still in the holes.

[Bitsyncmaster]

Would there be any thing against going from M7 to an M8 sized hole? I understand don't go deeper, but 1 mm larger? M8 is much more common then M7 and I might have to go that big to get out what is still in the holes.

I've done that in many places. It all depends on how much stock is around the hole.

[DMCVegas]

Ok, just throwing this question out here: Could leaving this car connected up to a battery tender have resulted in electrolysis that welded the bolts to the block?

I replaced my water pump twice (first one was defective) and had to fix a leaking O-Ring on the Y-Pipe and didn't have any problems at all with removing any of the bolts. Save for a single By-pass Flange on the Driver's side which was actually my fault for not chasing the threads upon reinsertion where I over-torqued it and snapped the head off. My car as an example was never maintained, just dumped on the side of a house after the owner died. So once the battery discharged, the car sat with 0 power for years.

[burch]

Would there be any thing against going from M7 to an M8 sized hole? I understand don't go deeper, but 1 mm larger? M8 is much more common then M7 and I might have to go that big to get out what is still in the holes.

Sorry to dredge up an old thread, but did you end up doing this? I had zero problems getting the manifold bolts out, however, I discovered the left rear (back of car) hole is stripped. Debating larger tap or going the helicoil route.

[BigBenb84]

I did go bigger. Everything is fine with it. I've put thousands of problem free miles on since doing this job.

[David T]

I did go bigger. Everything is fine with it. I've put thousands of problem free miles on since doing this job.

If you do find you have to go bigger the thing to do is to put the bolt in and then cut it flush. Now redrill and tap to the correct size. Best to try to keep all of the fasteners the correct size but if you have enough room it can't hurt to go bigger. It just becomes a pain if you have to work on it again, different size wrenches, keeping track of which bolt goes into which hole, enlarging clearance holes in parts, etc.

[vps3922]

You may as well weld your engine together.

:smile: lol! Awesome. That expression made my day!