Mercedes W114 250 Coupe - help!

[Bellow]

and that metal vacuum tube with the banjo unions that runs to the manifold- that could in theory be fabricated from nylon vacuum tube described earlier by Bellow but the banjo connections might be useful.

Given what I have subsequently seen since posting on the subject (the plastic pipes I referred to were for central locking) namely the smallness of the dashpot and ruggedness of the steel pipes - I can't help but suspect that significant vacuum is being tapped into. I'd fabricate from metal (copper/cunifer brake pipe) if they need to be made, sourcing a banjo from a fuel line application. Plastic may well collapse. Steel for a reason I think.

 

[Charles Morgan]

I officially love air impact wrenches. Once I'd managed to get a proper grip on the rusted nut on the backside of the ARB, and ground off the round knobbly bit that holds on the rubber bush the air impact wrench had the thing off in seconds.

Now clean and rustproof time.

 

[Bellow]

I officially love air impact wrenches. .

Noisy brutes of things - but brutally useful. The only thing that would shift the retaining bolt (or nut - I forget which) on my W123's steering wheel.

Can I ask a favour of you CM? Could you please, when you are next in the vicinity of your auto box, measure the outer diameter of the fluid coupling for me? Picture below should make it clear the dimension I'm after (the seam where the pumping rotor and impeller meet at the periphery). TIA.

 

[Charles Morgan]

Right, allowing for leaning over in the garden shed and the centre protruding so eye accuracy only - 28cms.

 

[Charles Morgan]

Just had a quick chat with the machine shop about cleaning up the cylinder head. David Knight at Knight's Engine Specialists nr Northampton said that such was the quality of the Mercedes castings and materials at that time it would be highly unlikely to need any valve hardening for unleaded, nor would it likely need new exhaust valves, just a clean up and new valve guides. Good news all round!

Oh and found a radiator re-coring company nearby too.

 

[Bellow]

Right, allowing for leaning over in the garden shed and the centre protruding so eye accuracy only - 28cms.

Thank you Good Sir - much appreciated.

Just had a quick chat with the machine shop about cleaning up the cylinder head. David Knight at Knight's Engine Specialists nr Northampton said that such was the quality of the Mercedes castings and materials at that time it would be highly unlikely to need any valve hardening for unleaded, nor would it likely need new exhaust valves, just a clean up and new valve guides. Good news all round!

Oh and found a radiator re-coring company nearby too.

Coming along nicely.

 

[Charles Morgan]

However, my attempt at removing the head bolts (I want to send off both heads and refurb the better one) with impact driver only released two of the 10. The others are now luxuriating in a veritable bath of Monolex! It may take some time...

 

[Bellow]

The Monolex will have tough time reaching the threads - though it will help under the bolt heads. Retorque the slackened bolts prior to attempting removal of the stubborns - it will take a little pressure off them. For now, better to leave them strained. Also, and preferably with a lever - attempt tightening the stubborns prior to removal. You may break their hold without jeopardising the bolt head hex faces you will need for slackening. Impact wrench would risk tightening them - irretrievably!

 

[Charles Morgan]

It shifted another 2 just now, so four of sixteen.

I shall do what you suggest tomorrow morning Mr B.

Noted on the impact wrench, it makes it easier for me to do a lot of damage!

 

[grober]

Its important to release the bolts in the correct sequence= the reverse order of tightening--- that's from both ends in towards the centre . Its also suggested to slacken them off each one a little at a time. If you actually removed the ones you freed up you might want to pop them back on and tweak em back up till you free the rest. When faced with stubborn bolts most people advocate shock and heat to break the threads free rather than sheer torque . An oxyacetylene torch or failing that a propane one with a localised flame might be of assistance here?

Bellow got there before me

 

[Charles Morgan]

I'd just slackened them, so have retightened them all, and found another two are capable of coming out.

Do I flame the bolt or the metal around it?

 

[John Jones Jr]

However, my attempt at removing the head bolts (I want to send off both heads and refurb the better one) with impact driver only released two of the 10. The others are now luxuriating in a veritable bath of Monolex! It may take some time...

I wouldn't use an impact driver. Good quality socket and pull bar. When I was in the same position as you are now I tightened the head bolts by literally a few degrees (in theory 1 degree would do, in practice it will be five) and very, very slowly loosened them again by a few degrees and repeated a few times. Take note, this worked without any issues on a BMW, not a Merc but similar vintage.

 

[Bellow]

I misread post#907. I read ten out - two to go! Not quite.

I'd just slackened them, so have retightened them all, and found another two are capable of coming out.

Do I flame the bolt or the metal around it?

The metal around so as to expand it clear of the thread. Works well with nuts but here I'd be extremely cautious as to heat localised spots of a casting is to risk cracking. Cast iron can be very unforgiving.
Even the notion of heating a bolt lacks real theory. All that can happen is it expands and pushes against the female thread and on cooling contracts breaking the grip. I'm not an advocate of the technique. Exposed nuts, yes - anything else, not really.
G is correct re release sequence. If the head is as I think it is (inlet valve flush with face) any warpage will be tricky to rectify.

 

[grober]

I'd just slackened them, so have retightened them all, and found another two are capable of coming out.

Do I flame the bolt or the metal around it?

Technically the metal round the bolt- but don't think it matters to much- its the expansion and contraction that does it. To that end 2 or 3 conservative heatings and coolings might just be better than getting everything glowing red hot. Point taken on Bellows warning on cast iron heads tho-- perhaps a technique of last resort!
Here's a video of a guy removing a Merc twin cam head- note the breaker bar technique at 3 minutes!
[YOUTUBE]6GJjiSkHykA[/YOUTUBE]

 

[grober]

dup

 

[Bellow]

Technically the metal round the bolt- but don't think it matters to much- its the expansion and contraction that does it. To that end 2 or 3 conservative heatings and coolings might just be better than getting everything glowing red hot. Point taken on Bellows warning on cast iron heads tho-- perhaps a technique of last resort!

The head is alloy (I think) and it is the iron block which would need to be heated. The expansion coefficient of cast iron is so low that anything short of red heat is unlikely to make a difference. Put the burner on the back burner and trust the slippy chemicals and cunningly applied mechanical force. They'll come.

 

[grober]

Can't quite remember if I posted this already or not?
http://s272261875.websitehome.co.uk/gal251981502/pdf/M180_rebuild_guide.pdf

 

[WDB124066]

Mercedes-Benz C280 Coupe 1970 | Trade Me

 

[Bellow]

Mercedes-Benz C280 Coupe 1970 | Trade Me

Oooh...stylish....

 

[WDB124066]

First class there Bellow - first class. Fit for Mr Charles himself!!