Soldering Hard Lines to Thermostat Advice Needed!

[Bill Jennings]

Hi All,
I am trying to resolder the hard oil line together immediately adjacient to the thermostat. This was an old repair by the previous owner that had started to leak so I took it apart. The lines had been crushed in several places by previous idiots being careless with jacking up the car and I was able to fix the worst of them with some heat and waterpump pliers. The flexible lines to the oil tank and engine are leak free but are showing their age.
I tried to solder it and the hard plumbing solder rod I am using took to the pipe itself but not the bit of pipe attached to the thermostat. I got both joints really clean and used the right flux for the solder.
The problem as I see it is that I can get enough heat into the hard line but not the bit of pipe attached to the thermostat as it is acting as a heatsink, and I would have to get the thermostat as hot as the pipe for soldering to work. I am using a mapp torch.
I have not tried to undo the pipe at the thermostat due to the horror stories I have read here regarding damage to the aluminium threads on the thermostat when trying to take the nut off.
I guess my options are:
1. Cut the nut off and get one of elephant racing's nuts then solder the two together.
2. Buy just one new line and cut the old one off.
3.Buy a full set of new lines, thermostat etc from elephant but the kit is circa $1600 plus shipping to Australia.
I know most advise replacement over repair due to the risk of catastrophic oil loss.
Plus looking at the poor overall condition of the lines I should replace the lot but would love to save a couple of thousand bucks if I can.
Cheers
Bill

This pic shows where the solder was starting to build up on the line.

[haasad]

I would try to remove the nut from the stat , the stat body is acting like a heat sink as you say, also its internals may not respond well to the level of heat you would need to apply to get a good joint.

A good tip to remove the nuts is to rest on nut flat on a solid surface and strike the opposite with a hammer a few times. Work your way around the nut flats doing this to fracture the corrosion build up which is siezing it. Keep doing this and flooding it with penetrating oil , a few heating cycles will help. Eventually the nut will come loose don't be tempted just to wind it off though, remove it by working back and forth a little at a time.
If it really wont come cut through it along the nut depth with a saw and open it up with a chisel to release it from the threaded stub on the stat. As you know elephant do the parts you need to reassemble.
I had real success hard soldering mine back together after I got them off the stat.

Good luck Andy

[JohnJL]

jb weld might be a last resort. your local enzed can make you up soft line replacements with the proper fittings.

[Bill Jennings]

Andy,
Many thanks for the tip on nut removal I'd not read about striking the nut flat before.
I have been using a mixture of ATF & acetone as penetrating oil on other fasteners will give your method a try.
Cheers
Bill

[john walker's workshop]

bite the bullet and get another complete line.

[Bill Jennings]

John,
That probably makes the most sense but I am dead scared of getting the nut off where it is screwed onto the oil cooler. I guess I can just dremel off the nut as the new line will have a new nut on it?
To be honest all four lines from the thermostat are well past their best and if I don't do them all now I know I will have to in the near future anyway.
Part of my motivation to repair rather than replace parts is that I have to pass registration in 3 weeks and if I miss that date due to shipping times from the USA to Oz then I have to go through a much more stringent exam called a blue slip here. It includes a noise test and car must be completely oil leak and rust free. I had to have the car engineered and blue slipped when I imported it two years ago but the guys who did them were pretty awed by the car and were lenient with me. They told me it was too loud and had a couple of rust issues and needed a passenger side mirror to be legal in Oz but let me off. I was hoping to do a quick fix to get through registration then fix it properly at my leisure.
I will call elephant on monday to see how long to ship a set of lines to me here.
I do appreciate the advice.
Cheers
Bill

[JohnJL]

Bill,
Yes, I know the blue slip thing, I had to go through it with a car when I lived in Sydney.

You might try wynns or prtechnology, thay may have some they removed for race cars going to soft lines.

[Targalid]

A quick fix, just to pass inspection, is to join the two pipes with a short piece of oil resistant rubber hose and hose clamps. Later you can repair or replace at your leisure.

[911SauCy]

Nice opportunity for Aeroquip lines and in-frunk t-stat relo.

[BoxsterGT]

I can offer some advice, as I have done a few of these in the past.

You must start with all surfaces absolutely clean. Brazing rod I what I use. The typical flux is available in white or black. Don't know the specifics, but the black seems to work the best for me.

From the looks of the results it seems you do not have enough heat. The pieces must be glowing orange for the braze to flow into the joints.

I just finished a few Fuel Fittings that are now NLA from Porsche.........



I had to clean the surfaces w emery cloth then sandblast them to get them clean enough to braze. Then sandblast them again so they can be zinc plated. Again, I must emphasize that clean is essential for a good bond.

Happy to answer any questions, but cannot send photos by PM, so I ONLY use email.

Len@Autosportengineering.com

[BoxsterGT]

Here are some 911SC Oil Hard Lines I am re-working to fit a 72 911 Oil System. This is a mock-up prior to brazing & Hose assembly................



Will find a photo of the finished product & post when I can.

Len

[john walker's workshop]

i like silver solder too. less heat needed and good and strong.

[BoxsterGT]

Hi John,

Actually these are silver soldered. When done these fittings are black & discolored but after cleaning & plating they look really good.

Here are a couple wide 180's (M10 x M08) I just finished for relocating a fuel pump up front in a 74 911..........



Cannot find my photos of the 72 front oil line mods but will post them when I can.

Len

[Bill Jennings]

Len,
I agree about getting the pipe absolutely clean and glowing orange to solder.
I was using a hard solder rod that needed quite a bit of heat before it melted.
I was able to get the long pipe orange but not the end that is still attached to the thermostat.
If I am going to retry this repair I need to decide if I am going to just cut the nut off or have a go at unscrewing it. It occurs to me that the PO must have had this nut off when he soldered it last time therefore it has been off at some point. No idea how long ago though!

So I guess my next question is if I can get the nut to move at all (after cycles of heat, penetrating oil and smacking the flats of the nut with a hammer) if it was fused together have I already damaged the threads? Or will it be obvious it is fused by not moving at all and the only resort is a cut off wheel?

Cheers
Bill

[BoxsterGT]

I have M30 Female Ball nipples & Male tube ends in stock. They are $8 and $10 ea respectively. I ship everything by Priority Mail at $6 for Flat-Rate pouch.

Unfortunately they are only steel so the must be rust-proofed afterwards.





The M30 Female Nuts (not shown) are plated so they will not rust.

Please email me for details. I do not accept PMs as I cannot send photos or track messages.

Edit: Forgot to say, save the T'stat & cut the nuts part way through in 2 or 3 places Use lots of "Weasel Piss" & hit it w an air chisel to spread/sacrifice the nut.

Len

[Trackrash]

Impact wrench? Set on a low setting, of course, after heating and soaking in penetrate.

[Bill Jennings]

Is the fitting I am trying to repair the standard fitting or did the previous owner repair replace it with something else?
It looks different to the other (original?) which shows brass between the nut and the brass oil line where the fitting I need to solder to is not brass it is silver in colour where I filed it, plus the nut is deeper and there are two or three exposed threads between the nut and the thermostat. Also the end is stepped rather like a garden hose or airline fitting!
This pic shows the deeper nut, exposed threads and the complete line in brass.


This pic shows where I ran a file across it leaving a bright shiny stripe.

I am currently preparing to attempt removal of the nut with cycles of acetone/ ATF penetrant and heat to the nut. How much heat should I use? I am also considering supporting the back side of the nut on my vise and smacking the top of the nut with a hammer. I can do three of the six sides of the nut this way. I am also going to try to pick the exposed threads clean for better penetration with my ATF mixture.
Cheers
Bill

[Bill Jennings]

Update,
Nut came off easily without damaging the thermostat.
I loosened it a couple of mill at a time then tightened again until it screwed off by hand!
Will clean every thing up and have another go at soldering.
If that fails then will order a new line.


Cheers
Bill

[BoxsterGT]

Good day Bill-

The part you have is definitely a "fix" by someone and not original. The bits in my photos above are "tube" ends, intended to be brazed or soldered. The part like this........



...is a M30 Female straight "hose" end or nipple. This is typically made of steel & Yellow Cad or now Clear Zinc plated.

Its still possible to repair, but the clearances are so great it would take a skilled person to fix this. I have learned to weld & braze a bit, but that would be beyond my skills for sure.

I could send you a repair section cut from a trombone cooler or similar and a coupling seen in my post #11. It would be no charge except for Priority Mail postage. That would run about $30 US. However, in the long run, a replacement line would probably be best.

Cheers,

Len Cummings

[Bill Jennings]

Len,
Very generous offer I must say however i'm not sure the pipe can take a coupler next to the old repair and might need to be cut further back so I am happy to pay you for making up this piece if you are willing to.

I was thinking of emailing you earlier anyway when I saw the pictures of what you can do, with a picture of the end of my hard line which has been deformed/enlarged by the previous fix thinking it needs to be cut back to good round pipe and a new piece soldered on with a new end for mounting to the thermostat.

I think the pipe has been shortened for the repair hence it is curved where the nipple enters the pipe.
I wonder if it needs to be cut back to where the pipe is straight?
Can you tell from the pics what needs to be done.
I also have my old trombone which is no longer required as I am intending to put on a carrera cooler I imported from a Pelican last year. So I have some useful parts here though am unsure if the nut I just removed from the thermostat would fit the trombone. The nuts on the trombone are toast.
Here are a couple of pics of what I am trying to describe.






I will drop you a email.
Cheers
Bill