I am trying to remove the radiator on my 960 so that I can create some space to remove a broken bolt. The top connector to the radiator is very tight and I am worried that I will break the plastic side compartment of the radiator if I apply too much torque.

I have applied PB Blaster and some tiger piss to the connector and I am letting it wait overnight.

It is a 17mm connector and I applied as much force as I could muster to the fairly large wrench without moving it. I also tapped it both ways to see if I could loosen it. No luck so far.

I am afraid of using a cheater to get more torque on the wrench because it could tear the whole connector loose from the plastic and a new radiator would be on the horizon.

Any thoughts?

I am trying to upload an image but as per usual I am failing.


Bob

Dear muskox27,

Hope you're well. The brass nipple, to which the steel ATF (automatic transmission fluid) pipe attaches, is braze-welded to the in-radiator ATF cooler. The cooler is a double-wall copper tube, with a hollow core.

To remove the ATF pipe from the ATF cooler's nipple, you'll need two wrenches. One wrench is used to hold the large brass hex nut that is directly against the radiator's plastic side tank wall and the other wrench (15mm, if I recall corrctly) is used to turn the steel hex fitting on the ATF line.

The large brass hex nut should NOT be moved AT ALL. The steel hex fitting on the ATF pipe should be turned, to loosen it.

While holding stock still the wrench on the large brass hex nut, push on the wrench on the steel hex fitting. Apply pressure until: (a) the steel hex fitting moves or (b) the steel pipe seems to twist.

If (b) occurs, apply more PB blaster and wait. It can take a long time for PB Blaster (or any other penetrating oil) to work its way through micro-channels in the corrosion and so to weaken the corrosion bond.

Were you to loosen the large brass hex nut and push on the ATF cooler's brass nipple, you'd break the seal between the inner surface of the ATF cooler's nipple and the inner wall of the plastic side tank. This won't allow coolant to enter the ATF. But breaking that seal will likely mean a bleed leak of coolant from the radiator and so a rad replacement.

Be advised that one or both of the ATF coolant pipes are no longer available from Volvo.

In short, use two wrenchs, turning only the smaller of the two wrenches.

Hope this helps.

Yours faithfully,

Spook

I don't know what it is about the 960,But I've had to replace the entire metal line a couple times over the years due to the line twisting at the nut.
Taking care and soaking the nuts I've still had twisting at the nut going to the radiator.

I did not check Brickboard before doing an early morning go around. If I had I would have held the brass collar nut as you instructed.

I did tap both ways and used a choke hold on a cheater pipe to get a little more [not a lot] torque and I was able to finally get the connector to turn.

The lower connector was not as stiff but again I did use a choke hold on the cheater pipe to get the initial turn.

Hope I have not broken anything more.

Now I can get the radiator out of the way. I will take a close look at it when I have it out.

I have invited a mobile mechanic to see if he can extract the broken bolt end from the front of the block. It is one of the bolts that holds the idler on to the front end of the block and I broke it when I misunderstood a torque setting to be ft-lbs instead of Nm and I tried to torque it to 30 ft-lbs. I know I do not have the skill set to attempt to remove it myself.

Just trying to replace the timing belt because it is overdue! It was running perfectly. Oh well.

I have squirted the bolt with PB blaster this morning. Hope this will help with the stub removal.

Nice to reconnect with some old friends from Brickboard though.

Dear muskox37,

Hope you're well. Clean the rear surface of the large brass hex nut, that which goes against the radiator's side-tank. Clean the side tank around where the nipple protrudes, as well.

Apply a thin layer of silicone sealant around the side tank's opening, through which the brass nipple protrudes. Replace the large brass hex nut and tighten 'til snug. When the sealant cures, it will contain coolant, just in case you broke the seal on the side-tank's inner wall, between the in-rad ATF cooler, and the side-tank's wall.

When you re-apply the steel fitting (to reconnect the ATF pipe to the nipple), coat the nipple's threads with some ATF. As ATF is oily, it will inhibit corrosion and so ease loosening of the fitting.

How far below the block face is the bolt stub? If it protrudes, it might be possible to cut a slot across the broken end, and then turn-our the stub with a screwdriver. If the stub if below the block's face, it might be possible to drill-out the stub. This is time-consuming but should work.

Hope this helps.

Yours faithfully,

Spook

Hi Spook,

I am going to take a chance on the radiator that I did not damage it. If it leaks it is not that big a chore to take it out again or to do some of the repairs you recommend. I could reseal the large brass nut right on the car or on the bench if the bottom nut proves to be the issue. I am a little nervous about moving the big brass nut and creating a problem.

The bolt stub is one of the two timing belt idler pulley bolts. It is about midway on the engine front face and is fairly accessible but I cannot get a face-on view. There is over a foot of working room for tools, etc. but I am very nervous about trying to drill it myself and damaging the threads in the process.

I will try tapping it and turning it with tweezers if it is unexpectedly loose. Otherwise I will leave it to a professional. Hopefully he will not mess it up.

muskox37

Dear muskox37,

Hope you're well. I concur. Leave the large brass hex nut alone, unless there's a bleed leak. The top nut can be resealed with the rad in place, if you drain enough coolant (into a pan) so that the area around the radiator side-tank opening can be dried, de-greased, and then accept a thin bead of sealant.

As to the broken belt idler pully bolt, if the stub protrudes, you may be able to turn it out with a vise-grip pliers. If I recall correctly, you over-torqued it, so the threads should not be corrosion bonded. Rather, it should take only a little extra energy to get it to move. If the bolt broke off below the surface, that's perhaps best be tackled by a professional.

Hope this helps.

Yours faithfully,

Spook

Yes, there is no corrosion. I was attempting to torque the bolt in place when it broke. At that point I was installing the new idler pulley.

I might try to give it a little tapping tomorrow to see if I can shake it loose. I have been steadily dosing it with PB Blaster over the last few days. Then I could make an attempt with tweezers. Otherwise I will leave it to the mechanic to drill it out.

It is not flush with the surface so there is no gripping it with anything. In fact it is about 1/8 of an inch below the surface.

I could try to take a picture but I don't have a lot of luck getting pictures to show on the website here.

Dear muskox37,

Hope you're well. If the bolt's stub is 1/8" (3.5mm) below the adjacent surface - and it was over-torqued - a tweezer will not move it. The stub is very tight. It is next-to-impossible for a tweezer to grip with enough force to enable the stub to be turned.

To extract an over-tightened stub, a hole must be drilled into the stub's exposed surface, using a drill bit of a narrower diameter than is the stub. Then, a screw extractor - a left-hand threaded tool with sharp-edged spiral flutes - can be inserted into the newly-drilled hole in the stub's top, and the stub turned-out.

The hard part about drilling the hole is centering the drill bit. If the stub's top surface is angled, it can be hard to use a center punch to make the "dimple", that keeps the drill bit centered until the drill bit "bites" in the stub.

hope this helps.

Yours faithfully,

Spook

Hello Spook,

This is about where my skill set ends. Trying to center the drill and avoid damaging threads is something I have never succeeded at doing well.

I was looking at some threads on stub removal but most of them were done out on a bench and were concerned with corrosion.

If I could get the end of a good bolt to screw into the first couple of threads I would consider taking a bolt to a machinist so that he could put it on his lathe and accurately drill a hole through the middle of it. Then I could screw the bolt on and drill through the centre without fear of skittering around and hurting the threads. I tried but there is not enough thread showing for the bolt to grip.

I will just have to hope the mechanic has a better skill set than me.

muskox37

"I will just have to hope the mechanic has a better skill set than me. "

Still in the shop?
--
Art Benstein near Baltimore

If speed counted, rabbits would rule the world.

Hello Art,

I finally did take the chance and I was able to extricate the bolt stub using a new regular drill bit and a reverse drill bit. I wasn't centred but I was able to get a fairly serious hole in the stub without hitting the threads and then it turned out fairly easily with the reverse thread drill. A great relief.

The rest of the job was fairly predictable but I did change out the serpentine belt tensioner pulley when it seemed to be too stiff. The new pulley was even more stiff so I might have been able to get by with the original--but it was a tad noisy when I spun it.

Regardless, it is all together now and I have been testing the car in all conditions. Should be good for another fifty thousand kilometres. Runs like a clock, much like it did before I took on the job!

Thanks for your input. Much appreciated.

Bob aka muskox37

Hi Bob,

Sorry, I missed your other thread as Spook kindly pointed out. I do, however, love to read of success when it comes to extracting broken bolts.

I've encountered this challenge enough to know to try my best to avoid further experience as best I can. Sometimes that's impossible. And my eyesight needs every aid known to the craft, so the experience I've gained is being discounted with every passing year.

Do you happen to remember Paul (Diamond Bits) Seminara? I think I learned a bunch about getting broken bolts out reading threads he participated in.

Thanks for the update!

--
Art Benstein near Baltimore

"I only have diamonds, clubs and spades," said Tom heartlessly.

Hi Art,

I am aorry but I do not remember Paul. Regardless, I can report the 960 is up and running like a clock once again. Keeping my fingers crossed that everything stays this way. I will be turning to the 940 sometime in the fall.

Broken bolts are the bane of my existence as an amateur mechanic and our best machinist moved away from town last year.

Nice to hear from you.

Bob Pellow
Parksville, B.C.
on Vancouver Island

Dear muskox37,

Hope you're well. Broken bolts are nasty, no doubt. One way to limit the risk is to saturate any fatory-original fastener with PB Blaster or a similar penetrating oil. It can take several days for the oil to work its way through micro-channels in the corrosion, so multiple daily saturations are helpful.

Second, once the penetrating oil has had time to work, start to remove the fastener by turning it as if you wanted to tighten it. There's no need to go more than .01 degree of arc. That slight pressure will help to break a corrosion bond. At once, reverse direction - to loosen - and apply gentle pressure. Then reverse, with little pressure. This is akin to rocking a car that is stuck in deep snow. Eventually one usually gets enough momentum to free the fastener.

Hope this helps.

Yours faithfully,

Spook

Rather than using the term rocking, I would prefer to describe it as sharp nudges in alternation directions of slightly increasing force to crack the bond in whichever direction breaks free first. Using a snug fitting wrench, especially a flare wrench, often works better than using a socket on a ratchet. Tapping the wrench with a hammer often works better at breaking the bond compared to a steady or jerking force. Continued rapid rocking of a stuck fastener can quickly lead to metal fatigue.

The most common stuck fastener that brickheads typically come up against is frozen brake bleeders. As Art said, experience usually comes with a few failures. With that in mind, probably best to practice pushing the limits of your skills on something other than a hollow bleeder nipple.
--
Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now

"This is akin to rocking a car that is stuck in deep snow."

Good analogy. Experienced snow drivers can do this by feel, without spinning the tires, and that's what you need to do to keep from breaking the bolt.

But the experience comes with a few failures.
--
Art Benstein near Baltimore

"I had so much petrol on me....after i took a shower, there was a benzine ring in the tub....." -BonesandFeathers

Good going on getting the broken bolt out. As for the tensioner pulley, people sometimes confuse the smooth stiffness of a new or near new pulley as being a sign of looming seizure. Generally speaking, pulleys spin more freely as the bearings wear until the bearings get so badly worn they suddenly seize up. For any pulley, any hint of noise or faint chatter from the bearings when it's spun is a sign it's high time for replacement. A pulley that spins freely should be spun a number of times to make sure there's no hint of chatter before re-using it. Any hint of slop is a sign of imminent failure. With the extended 100K change interval round toothed belts it's generally wise to always use a new tensioner. Same goes for any idler pulleys, such as found in the 16-valve B234F
--
Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now

I was just surprised that the new serpentine tensioner pulley was so stiff. The other pulley in the serpentine circuit spun easily but without noise so I kept it.

When I dismantled the tensioner to grease it the plastic bracket that is sandwiched between the top cover plate and the main body of the tensioner was in very poor shape. I removed it in crumbling pieces.

I then greased the six or eight holes in the main body of the tensioner and cut a cork style gasket to the shape of the cover. Just hoping this will not become a problem.

I get the feeling that people usually replace the entire tensioner and not just the pulley. This tensioner has probably been on the car since 1992.

Dear Art Benstein,

Hope you're well. I believe the job is complete, see:
https://www.brickboard.com/RWD/volvo/1667264/940/960/980/V90/S90/installed.html .

Hope this helps.

Yours faithfully,

Spook

Dear muskox37,

Hope you're well. It is the not drill bit that has to be centered. Rather, one takes a center punch - a hardened steel punch with a needle-sharp tip - and centers the punch's tip on the stub's surface.

One then hits the punch's flat top with hammer. With luck the punch doesn't move, so the hammer's energy flows through the punch's tip, and creates a "dimple" in the stub's top.

Using a 1/16" drill bit, one widens and deepens the dimple. Then, one takes a 1/8" bit and further widens and deepens the dimple.

Depending on the stub's diameter, one should then take a drill bit mated to the screw extractor - the diameter of which is proportional to the sheared bolt's diameter - and drills into the stub.

I'd guess a half-inch of depth should suffice. One inserts the screw extractor and then tries, by tightening the screw extractor - which is threaded opposite a standard thread - to turn-out the stub. It is important to go gently, so that the screw-extractor does not snap. It is made of very hard steel. Hard steel can be "brittle", so one needs to go gently.

This work takes care and patience.

Hope this helps.

Yours faithfully,

Spook

I know this an older thread and the problem has been dealt with, but for future reference of others faced with such a task I thought I'd add a couple of thoughts on removing bolts broken below or just barely above the surface, such as his tensioner bolt that broke 1/8" below the surface of the block.

Like many, I dislike using bolt extractors, especially on smaller diameter bolts. I don't do it often enough to have the feel and confidence that I won't break the brittle extractor and turn what started out as a challenge into a nightmare and likely expensive trip to a machine shop. Happened once years ago working on a lawn mower and I've been gun shy of screw extractors ever since.

My preference now is to reverse drill using left hand drill bits. I did this with great success on an outboard where multiple bolts holding the water jacket snapped off at the block -not at all uncommon in saltwater operation. The job went quickly and easily once I practiced going slowly on the first one.

The procedure is to drill a smaller pilot hole (like 1/8"-3/16") down the middle of the stub then move up to reverse drilling with a larger left hand bit that's just under the inner thread size so you don't damage the hole thread. You need to drill right through the end of the broken stub. There will normally be a gap at the end of the stub, so make note of when the bit hits that gap and jumps in a bit or the color of the chaff changes so you don't drill into the block any deeper than you have to -perhaps measure the depth of a nearby bolt of similar size to get a rough idea of how far you can go. You don't have to use reverse drilling for the pilot hole, but doing so increases the likelihood that heat from friction will break the bond and the stub will walk right out on the bit on the first try -it's a nice feeling when it does.

Now step up to reverse drilling with the largest left hand drill bit you can safely use without damaging the thread, basically one drill bit size smaller than the inner thread diameter (two sizes smaller if you drilled the pilot a bit off center).

Much of the time the remaining thread will spiral right out (well actually left out) on the final drilling. If not, try drilling with the next size up bit as long as you're not touching thread and then use a thread tap, which should be an easy task as it's metal stuck in corrosion, just be sure to keep rocking the tap in small increments, flushing debris from the hole occasionally as you go. You shouldn't need to use a bottoming tap unless the bolt goes all the way to the bottom of the hole -in such a case consider grinding the end of the bolt a bit shorter or drilling the hole a hair deeper rather than buying a bottoming tap.

Centering is of course very important, a bit more so than when using an extractor, so start by making a decent sized dimple with a center punch and small drill bit. I actually prefer using a diamond burr bit in a Dremel-type rotary tool for making such dimples, especially if it isn't broken off level or you can't get a good swing with a hammer or the punch you have is a bit large for the job and might damage the start of the hole.

Left hand drill bits are not usually available in retail hardware stores, so you may have to do a bit of phoning around. Start with automotive supply wholesalers or even ask a machine shop where to get them locally. You don't need to buy a whole set. Another advantage of using left hand bits is you won't use them often, so they stay nice and sharp for next time. The cost of a few drill bits and a thread tap is significantly less than a trip to the machine shop.
--
Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now

Looking at this image, you can see why the large nut is useless as a counterhold:


--
Art Benstein near Baltimore

“Never underestimate the difficulty of changing false beliefs by facts.” --- Henry Rosovsky

I see you got the lines disconnected. In my experience with older cars, I've never attempted to disconnect automatic transmission cooler lines. I've just cut them and then reconnected them using rubber fuel line and hose clamps afterwards. They're not high pressure. Yes, it's shade tree mechanics, not elegant.
--
1992 745, >500k km (now gone, but not forgotten)

That is good information. I have the radiator out now but if I had been unable to break the connectors loose your solution would have been very welcome.

Try to tighten it very slightly, then loosen. Heat gun and solvent. Are you using a flare nut wrench ? Using an open ended wrench only crushes/distorts the hollow nut tighter when trying to loosen or tighten. Flare Nut wrenches only on fitting like these. If you don't have one you can use a cut off wheel and make one from a 17mm box wrench.

Thanks for your information on the flare wrench as opposed to the open end. I will see if I can pick up a 17mm flare for the return journey when I go to tighten up the connector.

I got it off finally but haven't checked the rad to see if there is damage.

If the plastic side tank is in close proximity to the stuck bolt, I would not use a heat gun. Those plastic tanks become increasingly brittle with age and are known to crack and break even without torque or heat.

Stick with the solvents. After the solvent has sat overnight, and if it still doesn’t move, you might consider trying a few soft, well-placed taps on the nut with a small or ball pean hammer.
--
Will I buy another Volvo??? We'll see....

With a large adjustable wrench-hold the large nut in place with counter torque and with and flarenut wrench loosen the transmission line nut by a hard hit with your palm.
Jimo

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