Aftercooler bolts won't budge

[Constellation1]

I'm trying to remove the aftercooler from my Cummins QSB 5.9 and the four 15mm bolts that attach it to the engine are TIGHT. I will try a breaker bar tomorrow, as I didn't have one with me, but does anyone have any experience with this / tricks to try?

Thanks!

 

[4fun1]

Somebody may have used red locktite. The bolts on my QSB 6.7 had worked loose at one time and needed to be retightened. Not saying that is what it is but maybe.

 

[firehoser75]

Apply some penetrating oil like PB Blaster and let soak. Use several applications, then a breaker bar for leverage. If no luck, apply some heat to the joint concentrating on the "female" thread side, trying to expand the female side to allow removal?
Bolt removal can be troublesome.

 

[Simi 60]

Maybe this will help. (-;

 

[STB]

I had a bolt I couldn't get out of a coupling for the life of me. I used a lot of leverage, sprayed it with PB Blaster repeadly for an hour, and heated it with a MAP gas torch. I then soaked (immersed) the piece in PB Blaster over night. Still no dice.

I took it to a local machine shop (Godwin & Singer). They heated it red hot with a torch, then took an everyday candle and melted it into the interface, basically just moving it around like they were soldering. It got drawn right in and soaked up. And then the bolt spun right out easily. Threads on the bolt and coupler still perfectly intact.

I was totally amazed. They said they'd been using that technique in the shop for about 10 years and it was way better than oils.

 

[jleonard]

Yes that’s the way my son gets out bolts at his automotive shop except he uses crayons. Same thing get the wax between the two parts.

 

[Bill V]

I had a bolt I couldn't get out of a coupling for the life of me. I used a lot of leverage, sprayed it with PB Blaster repeadly for an hour, and heated it with a MAP gas torch. I then soaked (immersed) the piece in PB Blaster over night. Still no dice.

I took it to a local machine shop (Godwin & Singer). They heated it red hot with a torch, then took an everyday candle and melted it into the interface, basically just moving it around like they were soldering. It got drawn right in and soaked up. And then the bolt spun right out easily. Threads on the bolt and coupler still perfectly intact.

I was totally amazed. They said they'd been using that technique in the shop for about 10 years and it was way better than oils.

Thank you for sharing a great tip. In all the years of "mechanicing" I have never heard that tip, applying heat yes but using wax never. Just proves "never too old to learn something new".

 

[Lepke]

Really stubborn nuts and bolts will just break using the armstrong method.
The 2nd best way for rusted or locktite nuts and bolts is an impact wrench. You can rent an electric one from most tool rental places.

The best and easiest for steel is Kearney Rust Cutter. Made for transmission linemen working at the end of a helo. You spray it around the bolt hole or on the nut, wait a few seconds and they come apart easy. Best stuff I ever found for rusted bolts.
Available on ebay: https://www.ebay.com/itm/264237674511?epid=17030411613&hash=item3d85caf00f:g:bD0AAOSwEdteC4sk

 

[Pete Meisinger]

Check youtube. There are literally dozens of suggested solutions to try.

pete

 

[Comodave]

Really stubborn nuts and bolts will just break using the armstrong method.
The 2nd best way for rusted or locktite nuts and bolts is an impact wrench. You can rent an electric one from most tool rental places.

The best and easiest for steel is Kearney Rust Cutter. Made for transmission linemen working at the end of a helo. You spray it around the bolt hole or on the nut, wait a few seconds and they come apart easy. Best stuff I ever found for rusted bolts.
Available on ebay: https://www.ebay.com/itm/264237674511?epid=17030411613&hash=item3d85caf00f:g:bD0AAOSwEdteC4sk

I bought some of this on your recommendation and then have not needed it since...

 

[Arc]

There are different ways to remove the AC. There are brackets on the engine holding the cooler but there are bolts on the cooler to the bracket. I don’t take off the bolts on the engine , just the cooler.
Also if you are servicing the core, you can take off the caps and remove the core while on the engine. Assuming you have the room above the engine. 3 bolts top and bottom and just push the core up and out.

 

[Arc]

 

[ksanders]

I have found that a impact wrench can get things loose that I cannot do myself... and it won't break the bolt as easily as a huge breaker bar can.

Impact wrenches can be either air or battery powered.

 

[Comodave]

I have found that a impact wrence can get things loose that I cannot do myself... and it won't break the bolt as easily as a huge breaker bar can.

Impact wrenches can be either air or battery powered.

I use a battery powered 1/4” driver and if it won’t get it then go to the 1/2” battery powered driver. It usually gets it...

 

[Marco Flamingo]

Any of the PBlaster, Rust Cutter, or hot wax work for bronze on bronze? I have a 4" deck plate that is supposed to allow an emergency tiller to be dropped through the lazerette and provide steering if the hydraulic system goes out. It looks like the hydraulics haven't gone out in the past 40 years and the plate is frozen. Just curious if bronze needs to be treated differently than steel.

 

[ghost]

Check youtube. There are literally dozens of suggested solutions to try.

pete

My god, do you want him to find an answer or go down a rathole that could last years?


Nobody has mentioned kroil yet, but AVE tested it and did not really find it better. Smacking with a hammer pretty much came out on top of everything.

 

[catalinajack]

When you finally get those bolts out, reassemble using an anti-seize compound. Then, at regular intervals, at least once a year, loosen those bolts and retighten to ensure that this doesn't happen again.

 

[trihartsfield]

After heating them let them begin to cool before you try to loosen. I usually wait about 1-2 minutes. Sometimes you may have to heat and reheat several times.

 

[Constellation1]

*update* PB Blaster sat overnight, hit with hammer several times, breaker bar and the all broke free nicely. Thanks everyone.

For all of you QSB 5.9 gurus, I just noticed that there is a short fuel line that has to be removed as it goes between the the head and the fuel rail with the bracket in the middle. (not a diesel guy so apologies if that is incorrect). Any issue with disconnecting this on both ends?

 

[Tom Callan]

I'm trying to remove the aftercooler from my Cummins QSB 5.9 and the four 15mm bolts that attach it to the engine are TIGHT. I will try a breaker bar tomorrow, as I didn't have one with me, but does anyone have any experience with this / tricks to try?



Thanks!

I agree that you might need a little heat, I would use a torch with mapp gas is you have the space to properly use it, but first try a 6 point socket with a long breaker bar and gently apply more pressure, hope this works.

 

[RT Firefly]

Greetings,
When re-assembling, people seem to be pro or anti Locktite. Why not use simple lock washers?

 

[Ski in NC]

Aftercooler bolts on these can take some serious hoo-doo to get them to break loose. I use one 15mm wrench on the bolt, then another to extend the handle length. Note most have helicoils in the Al casting, so pretty durable.

 

[lwarden]

I've found that using blue Loctite on these sorts of threads has the added bonus of keeping water out of the threads and thus preventing corrosion. That or marine grade Loctite anti-seize.

 

[ronobrien]

If red Loctite was used, then some heat (torch) at the thread boss (female threads) will soften the Loctite. That red stuff should be used very judiciously.

 

[MVDarlin]

MAP gas torch and hammer. Wrench with cheater bar.

 

[Seevee]

Glad the OP got the job done.


For loosening bolts another solution is Aero Kroil, better than PB Blaster. Plus heat, carefully. Let soak for awhile, overnite, add heat and try. An impact wrench may help.


I've removed exhaust bolts on aircraft after 15 years of use... heating and cooling.


As for reassembly, I could argue to check the engine specs, if torque is needed, then torque it. But see if the mfg wants it torqued wet or dry and what additives they spec.