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Just secured a 450 SEL 6.9 after bit of a chase (years)

Started by andrewk, 18 October 2022, 07:38 AM

daantjie

Heat gun too lightweight for this jobby I'm afraid.  You need direct flame from a propane type torch like a Bernz - O - Matic or similar for that sucker.  Red hot then cool a bit then have a crack at it.
Daniel
1977 450 SEL 6.9 - Astralsilber

andrewk

Quote from: daantjie on 08 January 2023, 10:23 PMHeat gun too lightweight for this jobby I'm afraid.  You need direct flame from a propane type torch like a Bernz - O - Matic or similar for that sucker.  Red hot then cool a bit then have a crack at it.

I have both propane/butane-isobutane and MAPP torches too... but it's on the car chassis. Non-removable bracket...
I do like a good fire though, and the fuel tank is now out of the car.
1979 450 SEL 6.9 (#5532) - silbergrün metallic

BCK1963

Hi Andrew,
I suppose that the radiator shop guys know what they are doing and basically all described steps seem reasonable. Though, the step of rust removal is not apparent to me. This pickling is usually done with an acid, followed by neutralization and excessive rinsing with water. On the other hand the tech data sheet of RedKote says that it it capable of incapsulating slight rust, it is said to even close small leaks.

As you say the old coat is removed with ketone solvents.
The RedKote is a polymer which contains 50 % chlorine and 50 % hydrogene (by atom numbers, not weight) along the carbon polymer chain. You may call it an improved PVC which contains only 25 % chlorine. The higher the amount of chlorine, the more polar it is and the higher the resistance to non-polar hydrocarbons. Standard PVC is not long-term resistant to gasoline.
Polyvinylidene chloride / PVDC is not that widely used, more common is polyvinylidene fluoride, or PVDF. This is very similar to PVDC, only that there are fluorine atoms in the place of chlorine atoms. When adding more fluorine at the expence of hydrogen you finally end up with PTFE / Teflon, which contains 100 % fluorine atoms along the carbon chain. I suppose that PVDC is used for solubility reasons.

So much for the little chemical detour from the mechanical main road.
Bernd

1976 Merc 6.9  since 2013

andrewk

Quote from: BCK1963 on 09 January 2023, 03:44 AMHi Andrew,
I suppose that the radiator shop guys know what they are doing and basically all described steps seem reasonable. Though, the step of rust removal is not apparent to me. This pickling is usually done with an acid, followed by neutralization and excessive rinsing with water. On the other hand the tech data sheet of RedKote says that it it capable of incapsulating slight rust, it is said to even close small leaks.

As you say the old coat is removed with ketone solvents.
The RedKote is a polymer which contains 50 % chlorine and 50 % hydrogene (by atom numbers, not weight) along the carbon polymer chain. You may call it an improved PVC which contains only 25 % chlorine. The higher the amount of chlorine, the more polar it is and the higher the resistance to non-polar hydrocarbons. Standard PVC is not long-term resistant to gasoline.
Polyvinylidene chloride / PVDC is not that widely used, more common is polyvinylidene fluoride, or PVDF. This is very similar to PVDC, only that there are fluorine atoms in the place of chlorine atoms. When adding more fluorine at the expence of hydrogen you finally end up with PTFE / Teflon, which contains 100 % fluorine atoms along the carbon chain. I suppose that PVDC is used for solubility reasons.

So much for the little chemical detour from the mechanical main road.

Bernd, A detour to chemistry land is always welcome. I asked about the lack of hydrochloric acid pickling step  as it makes sense to use an acid to reduce the Iron oxide but the answer was simple; it tends to weaken the tank if it already has rust and creates more pitting/pinholes. Then a hot caustic solution is for dissolving the Zinc plating and exposing raw metal in other areas, not just removing other contaminants. He said the Mercedes tanks were some of the best around due to the Zinc plating, where others were bare metal and long disintegrated, especially so with hygroscopic ethanol-containing fuel. The subsequent washing steps need to be done with cold water to lower the rate of oxidation. It would be too difficult to Zinc plate an old tank unless it was cut open and sand blasted, cleaned perfectly. By that stage you're better off making a new tank from hot galvanised steel and conformal coating it with some kind of urethane/epoxy.

I am also curious about the choice of reagents used in this coating. Many halogenated compounds (typically those with Bromine or Fluorine) tend to come with other baggage - persistence in the environment (especially with Fluorine... e.g. PFOA/PFAS family), health concerns, solubility problems, cost, difficult of manufacture. PTFE would be a great, near ideal non metallic coating for the inside of a theoretical fuel tank as it has wonderful chemical resistance but it's essentially insoluble in everything and quite difficult to handle.
1979 450 SEL 6.9 (#5532) - silbergrün metallic

rumb

Hot air gun wont cut it to loosen brake/hydro lines.  Heat it up with a torch should do though.

Use Cunifer copper nickel brake line, NOT regular copper.

https://www.brakeconnect.com/4-reasons-to-use-cunifer-copper-nickel-brake-line
'68 250S
'77 6.9 Euro
'91 300SE,
'98 SL500
'14 CLS550,
'16 AMG GTS

andrewk

Thanks all for your help.

Actually, a contact has found a replacement original part - 123 420 54 28 64 which seems to be used on very many Benz models. It will likely work out cheaper than buying a roll of tubing, tools and fittings, and be original.

Unfortunately the sway bar bushing is unavailable from Mercedes Benz... I'm going to ask Niemöller and see if they can get the part, else, I might have to put the feelers out to you all to see if I can find spares. They are perished, and this will likely translate to either bad handling, noises/clunks or issues with the HPF.
1979 450 SEL 6.9 (#5532) - silbergrün metallic

raueda1

Quote from: andrewk on 09 January 2023, 07:30 AM
Quote from: BCK1963 on 09 January 2023, 03:44 AMHi Andrew,
I suppose that the radiator shop guys know what they are doing and basically all described steps seem reasonable. Though, the step of rust removal is not apparent to me. This pickling is usually done with an acid, followed by neutralization and excessive rinsing with water. On the other hand the tech data sheet of RedKote says that it it capable of incapsulating slight rust, it is said to even close small leaks.

As you say the old coat is removed with ketone solvents.
The RedKote is a polymer which contains 50 % chlorine and 50 % hydrogene (by atom numbers, not weight) along the carbon polymer chain. You may call it an improved PVC which contains only 25 % chlorine. The higher the amount of chlorine, the more polar it is and the higher the resistance to non-polar hydrocarbons. Standard PVC is not long-term resistant to gasoline.
Polyvinylidene chloride / PVDC is not that widely used, more common is polyvinylidene fluoride, or PVDF. This is very similar to PVDC, only that there are fluorine atoms in the place of chlorine atoms. When adding more fluorine at the expence of hydrogen you finally end up with PTFE / Teflon, which contains 100 % fluorine atoms along the carbon chain. I suppose that PVDC is used for solubility reasons.

So much for the little chemical detour from the mechanical main road.

Bernd, A detour to chemistry land is always welcome. I asked about the lack of hydrochloric acid pickling step  as it makes sense to use an acid to reduce the Iron oxide but the answer was simple; it tends to weaken the tank if it already has rust and creates more pitting/pinholes. Then a hot caustic solution is for dissolving the Zinc plating and exposing raw metal in other areas, not just removing other contaminants. He said the Mercedes tanks were some of the best around due to the Zinc plating, where others were bare metal and long disintegrated, especially so with hygroscopic ethanol-containing fuel. The subsequent washing steps need to be done with cold water to lower the rate of oxidation. It would be too difficult to Zinc plate an old tank unless it was cut open and sand blasted, cleaned perfectly. By that stage you're better off making a new tank from hot galvanised steel and conformal coating it with some kind of urethane/epoxy.

I am also curious about the choice of reagents used in this coating. Many halogenated compounds (typically those with Bromine or Fluorine) tend to come with other baggage - persistence in the environment (especially with Fluorine... e.g. PFOA/PFAS family), health concerns, solubility problems, cost, difficult of manufacture. PTFE would be a great, near ideal non metallic coating for the inside of a theoretical fuel tank as it has wonderful chemical resistance but it's essentially insoluble in everything and quite difficult to handle.
Wow, this is making me nervous!   :o   

I did the whole tank cleaning thing 4 or 5 years ago.  My tank strainer was half clogged with rust particles so the strainer was replaced.  I pulled the tank and cleaned it out in stages.  First was repeated rinses with "orange cleaner" until the rinses were clean.  Then that followed by water rinses which were also clean.  Then several "drying" rinses using denatured alcohol stove fuel followed by further drying rinses with acetone.  These were water-white.  All the other filters were replaced &/or cleaned, followed by years of trouble-free driving.  I've used ethanol-free fuel about 75% of the time.  But I never tried to coat the tank as described.  Yikes.  How concerned should I be?  Great job on all this, BTW.  Cheers,

-Dave
Now:  1976 6.9 Euro, 2015 GL550
Before that:  1966 230S, 1964 220SE coupe, 1977 Carrera 3.0

rumb

1163261381 rear sway bar bushing is available from MB @$30 each.

Probably  has to come from Germany.
'68 250S
'77 6.9 Euro
'91 300SE,
'98 SL500
'14 CLS550,
'16 AMG GTS

andrewk

Quote from: rumb on 11 January 2023, 06:31 PM1163261381 rear sway bar bushing is available from MB @$30 each.

Probably  has to come from Germany.
Where do you get the info? Pelican advised that Germany has none, some weeks after placing the order. If I order it from the dealer here they tend to charge 3-5x what it costs to get it from Classic Center and it take 6-8 weeks to arrive but I have asked them if they can order it anyway, as they are very close to my house and workplace and the parts guy has been very helpful. Just not great pricing for big ticket items...
1979 450 SEL 6.9 (#5532) - silbergrün metallic

andrewk

Quote from: andrewk on 11 January 2023, 07:05 PM
Quote from: rumb on 11 January 2023, 06:31 PM1163261381 rear sway bar bushing is available from MB @$30 each.

Probably  has to come from Germany.
Where do you get the info? Pelican advised that Germany has none, some weeks after placing the order. If I order it from the dealer here they tend to charge 3-5x what it costs to get it from Classic Center and it take 6-8 weeks to arrive but I have asked them if they can order it anyway, as they are very close to my house and workplace and the parts guy has been very helpful. Just not great pricing for big ticket items...


MB Sydney also responded that the bushings are NLA/discontinued. The saga continues...


1979 450 SEL 6.9 (#5532) - silbergrün metallic

rumb

'68 250S
'77 6.9 Euro
'91 300SE,
'98 SL500
'14 CLS550,
'16 AMG GTS

andrewk

1979 450 SEL 6.9 (#5532) - silbergrün metallic

andrewk

Unfortunately when I removed the warm up regulator (which was full of some kind of particles and fuel varnish), one of the threads stripped, taking a bit of the Aluminium with it. So, I have purchased a Time Sert thread repair kit and will repair both threads just in case the other is wrecked - and to ensure even expansion when the motor heats up. I have received a rebuilt warm up regulator and obtained new fittings from K-jet.biz to get it reinstalled and working correctly.


I also removed the front brakes to be sent for rebuilding and the rear callipers are rebuilt, coated with high temperature urethane paint and ready for reinstallation (pictures coming soon). I found the brake lining sensor wiring insulation to be completely disintegrated so I have removed that so I can build or obtain replacements.
Pro tip: undo the two bolts on the steering knuckle and swing the knuckle out of the way to get better access to the other bolts which hold the calliper in place. As one of the callipers was seized and I struggled to remove the pad retaining pins, I just loosened the four bolts holding the calliper together so I could get it off the disc, which is also going to be replaced (lots of wear and heavy corrosion on the edge. New ATE parts on hand, OE parts discontinued from the looks of things.

The fuel tank has also been cleaned, stripped, coated internally and repainted. Further parts have been removed for Zinc plating and passivation

I am just waiting on the vacuum hose connecting part and fuel level sender from MB Classic (will post pictures and part numbers when they arrive) also some fuel hose to connect the breather and return lines to the tank and charcoal/activated Carbon canister.

Getting very close now...

1979 450 SEL 6.9 (#5532) - silbergrün metallic