Is it hard to repair my own oil cooler brass lines on my 911 Carrera?

[Determined]

Has anyone had any success with repairing their own long oil cooler brass lines? I'm considering cutting a section out and trying to reshape the tube from the inside then silver soldering a new section back in, is this a good or bad approach?

Best Regards,

Alex
76 911 Targa with 3.2L Carrera and front oil cooler.

[Porsche84]

What is your problem? If it is one bent tube and it's not leaking, I'd ignore it. If a bunch of tubes are messed up, it would be a good opportunity to go to a better cooler. If you want to save this one, you might check out Pacific Oil Cooler, they do great work and it will be perfectly clean when done. http://www.oilcoolers.com/
You need to be very careful not to end up with any metal contaminants in your cooler when you are one. Good luck

[ChrisBennet]

I think he means the long lines leading to the cooler Jerry.
-Chris

[Determined]

Gentlemen,

I'm sorry for the confusion, I was referring to the long brass tube oil lines running from the front oil cooler to the passenger side rear thermostat.

Best Regards,

Alex

[911pcars]

If you can show us the damage to your line, I'm sure we'll have suggestions for a repair or replacement solution.

Sherwood

[Elombard]

3/4" plumbing copper sleeves are a very nice fit outside of the stock lines (at least on the 964 lines). I think you should be able to et a good seal using a sleeve. Not sure if you are tryign to butt weld.

[Porsche84]

Alex

Sorry for MY confusion. Chris knows that I get confused unless I have a fresh batch of cookies. I thought you were refering to the 27 tube oil cooler. I'd suggest trying to silver solder tabs on the dent and try to pull out the dented area, like the body shops do to remove fender dents. The next choice would be to drill a hole or two and insert something to pull out the dent, then silver solder the holes you drilled. The final option would be to cut out the section and replace it using a slip fit and sweat it on with silver solder. Good luck

[Walt Fricke]

I read the post the way Jerry did, too. The idea of soldering tabs and pulling is interesting. Sounds like you might be able to do that without removing the pipe. I'd not be too interested in drilling holes, though if you had the pipe off the car I suppose you could clean out the shavings.

I had a line repaired by cutting it in or near the dent. A mandrel was used to make the line round again, and a thin sleeve was machined and inserted so it bridged the cut, something was used as a solder, and all was well but for the slightly smaller inner diameter at the repair. You'd have to know this had been done to see the repair.

But I like hearing that 3/4" copper pipe couplings are a good fit over the outside (some day I'll measure the lines on my '77 to see if this holds for them). Combine that with making the pipe nice and round again with various tapered punches and round shapes and you should have a very cost effective repair.

A trick way to make a dented pipe round again is to block one end and put an air pressure fitting on the other and pressurize the pipe. Then heat the dent and let the air pressure do the work. I understand that this will take a very deft hand, as the usual result otherwise is to blow a hole in the pipe. Which is why I haven't tried this. I think it is more commonly done on exhaust pipes. Steel may be more forgiving than brass.

Walt Fricke

[Scott Wolthuis]

Alex,

I repair these as a hobby. I've built some tooling to repair them without splicing and do this for local Dallas/Fort Worth shops as well. These lines are .860 O.D. so the 3/4" sleeve may not work. I have lines for sale, repair or exchange basis but shipping is about $50 the last time I shipped some.

Good luck with the repair, if you give in and have trouble finding a replacement PM me.

Scott

[Determined]

Scott,

I agree on the outer dimension, I measured an I.D. of about 3/4 inches as well. A brass sleeve with an O.D. of 3/4 inches and silver solder may do the job, at least I think so. I believe that silver soldering is better because of the higher melting temperature, what do you think. Oh, can you please PM me with replacement costs for one oil line.

Thanks,

Alex

[Fishcop]

The heat and pressure method definitely works and will not blow the line.

Crushed/Dented Oil Lines... Fix?

[ficke]

3/4 inch brass pipe couplers fit real nice over the oil pipes and I thought it would be a pieace of cake to solder repair my lines. I could not get them clean enough to solder well so after cutting and fitting the repair I had a friend with a rad. shop do the soldering. I am sure some one with more patience and better acid could have done it at home.

[Walt Fricke]

No doubt silver solder is a better filler. But I've never been able to make the stick I bought work. Don't know why, but I can't get it to wick no matter what flux I use and how clean things are and using an acetylene torch to get things nice and hot.

Regular plumbing solder, on the other hand, is pretty easy to use on copper or brass. I have some short pieces of copper pipe and pipe fittings soldered together up at the two Continental aircraft oil coolers in the nose of the race car. They have been there maybe 10 years now. With a turbo pump pushing that hot oil they probably see as much heat and pressure as you'd see in a stock setup, if not more. Solder starts softening well above the temperatures you'll see in your oil (if it gets hot enough to soften solder you've got larger problems). However, if I could silver solder I would - why not use something a bit stronger than you need.

The only problems I have had are the result of soldering a fitting which is screwed into a large piece of aluminum (oil radiator tank) - tricky to get enough heat into the solder joint area. But those leaks are soon apparent and after enough tries everything is well tinned and finally seals.

I am glad to know that you can use 80 psi and that you should not blow out the line pressure straightening. My friends (a highly experienced Porsche dismantler/owner/car builder and a mechanical engineer customer needing the long lines for his car) blew out a couple and gave up, so I figured it was tricky. And thanks to the post giving the previous thread which described pulling round balls through.

Walt Fricke

[Scott Wolthuis]

Alex,

I would go with the tube (doubler) to the outside on the O.D. - no added oil restriction that way. Cars with restricive systems are burning more power pumping oil ,especially if the bypass on the thermostat is opening. Silversolder works for me, wall thickness is about .030" so watch your heat. With heat and pressure blowing a hole in it comes down to heat vs. pressure. Go for it!

Scott

[s5uewf]

Several folks in the Dorkiphus community have been able to successfully use the method whereby pressure is used to pressurize the tubing, heat is applied, and then re shaping
is performed. It has apparently saved people from having
to replace the tubes.

[Determined]

Thank you everyone for your input and advice, it has been very rewarding to hear all of them.

Best Regards,

alex