Merc thread

[wuvvum]

I assume heating would require an oxy-acetylene setup and my little propane blow torch would be as much use as a fart in a hurricane?

[spike60]

I don't know it may be enough, I only heat them gently always moving the flame round and round and trying to keep the flame on the inside  of the ring away from the teeth.  You don't want focused heat especially on the teeth as this will affect the tempering. I've heard of it being  done on an electric 4 plate hob dropping the ring onto the flywheel once hot but I haven't, I've only used oxy/acetalyne.  A blow torch may well be enough, we have welders but don't ask them to do it as they go into everything on max. Be sure to get the ring on the right way round, some have a lead on one side of the teeth.  

[paulplom]

Be careful and whatever you do, do not drop the gearbox on your head.

[lanciamatt]

A blow torch would probably work, it would just take longer to do it. Just make sure your in a area where not much wind blowing as you don't want that to cool it. 

[spike60]

The ones I have usually done are on a bit larger engines , usually old 7.1 Volvos and more recently Merc om 906 6.9 but I also fit them to Nissan 2.5 TD which is probably something similar. If it's a good torch I can't see why not. If you try and fail you could take it to an old school garage or engineering shop and they should be fine. 

[spike60]

Back to the heater plugs, if you have a meter you can test with you can test the resistance between the main body and the terminal the lead goes to. You don't need to remove them for this , just take the power lead off. Any bad apples should stand out from the others but the ones I've tested have a very low resistance, it's important to know the testers leads resistance and not add it in, as I have! Or with a good battery and some heavyish leads just directly short the plug, it should err, glow on the tip in a few seconds.

 

[spike60]

Easiest tip for driving a manual with 1 bad patch  of flywheel teeth is to stall the engine, don't switch it off. Odds of settling on the bad patch again are slim.

[Asimo]

16 hours ago, wuvvum said:

I assume heating would require an oxy-acetylene setup and my little propane blow torch would be as much use as a fart in a hurricane?

Gas cooker is ideal. All burners on gently, move ring around through flames to heat it evenly  Place a bit of solder on the new gear, when it begins to melt it is hot enough. (200 - 250 Centigrade)

[wuvvum]

5 hours ago, The Mighty Quinn said:

Another tip for starting a car with a fucked ring gear: park on a slope and with the car in 1st gear, let the hand brake off, release the clutch and it'll nudge the engine round a bit. Then the starter will catch.

Good idea, but I live in Norfolk...

[wuvvum]

I refitted the starter motor today.  I'm not going to be able to get anyone to do any machining or owt until we're out of lockdown, and the rest of the car's electrics depend on the starter being fitted (there's just a single cable from the battery live terminal which goes straight to the starter, and the rest of the electrics pick up their live feed from there), which meant I couldn't play with anything else whilst the starter was off.

I also wanted to see whether winding the engine over by hand (or rather by a ratchet on the crank pulley, having removed the radiator fan) until the starter was by a decent section of ring gear teeth would be enough to get the engine to start.  The answer is no - the starter will engage and turn the engine over very briefly, but it hits knackered teeth and disengages long before it gets the engine turning over enough to fire up.  It did however manage to stay in for long enough, with reverse gear engaged, to roll the car backwards off the ramps, so that saved me a lot of pissing around with jacks.

The other job I wanted to do was to check which brake(s) were seizing on, so I jacked each corner of the car up in turn - it seems it's only the nearside front which is badly stuck, the other three wheels I could turn by hand with relative ease, but with the nearside front even when I grabbed the wheel in a bear hug and put my back into it I could barely move it at all.  So next weekend's job is to try and get the caliper off and see if it can be freed up - then I'm going to have a go at bleeding the brakes to see if I can get a decent pedal.  If I do have to take it somewhere to be worked on, it'd be useful if I can drive it there (having got a bump / tow start off an obliging neighbour) rather than faffing around towing it, and the brakes are now the only thing really stopping it from being drivable once the engine's running.

[wuvvum]

Oh, and I found a place in Germany that will sell me a new ring gear for 35€ (plus 18€ postage), so that might be the way to go if I eventually get the flywheel off, rather than trying to flip the existing knackered ring gear round.  Especially since I found while winding the engine over by hand earlier that one of the teeth has completely snapped off.

[wuvvum]

Didn't get much done on this today as the weather was shite for most of the day, but I made a start on getting the nearside front caliper off.  The caliper bolts came out easily enough, but the caliper was stuck fast onto the disc - and there is a significant lip round the edge of the disc, so even if I had managed to get the caliper moving it probably wouldn't have come all the way off.  So I had to loosen the four Torx bolts holding the two halves of the caliper together and partially split it in half - that got the caliper off the disc, at the expense of a significant quantity of brake fluid. 

The pads are moving freely on the locating pins, so it's obviously one or both pistons which are seized.  To investigate further I need to get the caliper off the car, but unfortunately where the flexi screws onto the caliper is slightly* rusty so I have a horrible feeling it's not going to come undone without a fight.  I've soaked it in GT85 and left it overnight and I'll try again tomorrow but I'm not holding my breath.  I did consider trying to undo the flexi at the top and remove the whole thing along with the caliper, but that's going to be awkward as well - again things look a tad rusty, plus I won't be able to get my brake pipe spanner on the end (even if I can find said spanner, which I can't at the moment) as the poxy spring clip thing which holds the flexi in place is right in the way.

Have I ever mentioned I hate working on brakes?

On a more positive note, if the caliper does turn out to be toast, at least calipers for W115s seem to be both more plentiful and far cheaper than their Volvo 164 equivalents.

[Angrydicky]

1. Heat the end of the flexi.

2. Hacksaw through the flexi above the flats and find a suitable (preferably an impact) socket which will hopefully shift it.

You will also need to get considerable amounts of heat on that piddling little bleed nipple before attempting to move it - i.e. glowing - it will probably shear off otherwise. Preferably once it's apart.

We use a hydraulic pump to remove pistons at work. You will need a flexible extension on whatever you're using (grease guns with handles work) and an M10 x1 adaptor. You will need a couple of caliper piston clamps as well. You might be able to use a couple of G clamps but they will probably get in the way. You'll definitely need to bolt the two halves back together to do this trick. 

The advantage of buying these tools is that you can use them to do your Volvo caliper as well.

[spartacus]

If you need to take the starter off but still need power to the rest of the car can't you just bolt the cables together, then wrap them in insulating tape.

I've no doubt that all the ring gear removal/refitting suggestions above work but just to add another experience, I've always split old ones off with a chisel, then heated the new ring gear in the oven, I've never needed to put the flywheel in the freezer, although I'm sure it'll work, the science is there!

I've taken a ZF auto box out of a BM 528 in a similar way to how you're going to have to work, I used a trolley jack and laid a thick sheet of ply under the car for it to move on. You used to be able to buy an attachment for trolley jacks to secure a gearbox to, Machine Mart I think.

[wuvvum]

2 hours ago, Angrydicky said:

1. Heat the end of the flexi.

2. Hacksaw through the flexi above the flats and find a suitable (preferably an impact) socket which will hopefully shift it.

You will also need to get considerable amounts of heat on that piddling little bleed nipple before attempting to move it - i.e. glowing - it will probably shear off otherwise. Preferably once it's apart.

We use a hydraulic pump to remove pistons at work. You will need a flexible extension on whatever you're using (grease guns with handles work) and an M10 x1 adaptor. You will need a couple of caliper piston clamps as well. You might be able to use a couple of G clamps but they will probably get in the way. You'll definitely need to bolt the two halves back together to do this trick. 

The advantage of buying these tools is that you can use them to do your Volvo caliper as well.

Greatly to my surprise, the bleed nipple came undone with no problem at all.

I'll try heating up the end of the flexi, see if that helps get it moving - I'd rather avoid chopping through the flexi if possible as I can see it being a royal pain in the arse to get undone from the top end so I want to keep it intact if at all possible.

The grease gun method might well work on this caliper - I'll give it a try, I've got a "proper" grease gun in the shed.  Presumably grease works as well as brake fluid for pumping pistons out (even if it is more of a pain in the arse to clean up afterwards)?  A mate of mine has actually built a pump using an old master cylinder and a big lever, but obviously I can't go and use that at the moment. 

It's a bit more awkward with the Volvo caliper as it has two inlets and four pistons - the Merc effort is rather simpler.

[wuvvum]

13 hours ago, spartacus said:

I've taken a ZF auto box out of a BM 528 in a similar way to how you're going to have to work, I used a trolley jack and laid a thick sheet of ply under the car for it to move on. You used to be able to buy an attachment for trolley jacks to secure a gearbox to, Machine Mart I think.

I'm sure I'd be able to get the gearbox out with few issues - it's getting the fecker back in that I'm worried about!

[wuvvum]

Got the flexi undone from the caliper with the aid of a bit of heat.  Had to split the caliper again to get the pads out, but the bolts came undone easier second time around.  I think the flexi might be shagged though as I had a lot of trouble bleeding the caliper - even heaving on the pedal very little fluid was coming out.  Pumping the pistons out was equally difficult - although I was pleased to find that my big G-clamp is the perfect size for both clamping them in place and winding them back in.  Both wound back in with a little persuasion, so they're not completely seized which is good.  The dust seals have had it though so those at least will need to be replaced. 

Closer examination of the join between the top of the flexi and the metal brake pipe coming down from the master cylinder has revealed that they don't have an icecube's chance in hell of coming apart.  The union is rotten, and it's also rusted onto the (steel) brake pipe.  Only way to get the flexi off is going to be to hacksaw through the metal pipe and pull the whole lot off, then make up a new master-cylinder-to-flexi pipe.  Fortunately the master cylinder is right over on the left of the engine bay so the pipe is only about 10" long, and I've got half a reel of brake pipe in the back of the Toyota - just need to find what I've done with my flaring kit...

For now I've stuck the caliper back on sans pads so the car can be rolled if required.

[wuvvum]

So what with today being VE Day I thought I'd attempt to replicate the events of 75 years ago and show this bolshy German who's boss.  It didn't go well.

The idea was to pump out the caliper pistons, give them a quick rub down if need be, grease them and then refit them with the new dust seals.  I got one piston to pump out this far:

Then the piston seal went and further pumping just resulted in it pissing out brake fluid - the piston didn't budge.

I could probably pump it out using a grease gun (grease being much thicker than brake fluid) if I could find an adaptor, which I've had little success with so far.  However the piston looks quite badly pitted, and I'm assuming the other one is going to be in a similar state given that the dust seal on the other side is equally shagged.  It's getting on for 40 quid for a new pair of pistons - given that I can buy a complete, brand new caliper for £75 delivered I might end up taking the coward's way out.

I'm still no further towards deciding how best to tackle the flywheel issue.  Easiest way (if I do it myself rather than getting a garage to do it) would be to hoik the engine and gearbox out complete through the bonnet, then split them once out of the car.  The problem is where to do it - my drive isn't really big enough and I'm not sure the engine crane would be very easy to use on gravel anyway.  I don't really want to do it out on the road, and it's asking for trouble if I try to perform open heart surgery on the car park.

I might just have to find a nice long hill to park it at the top of so I can just bump start it when I want to go for a drive.  Although living in one of the flattest parts of the country is a bit of a drawback with that idea.

[jonathan_dyane]

I would vote for a new calliper.

On the ring gear if the access is good enough through the starter aperture it might be possible to build the problem teeth up with weld and profile with dremel?

[wuvvum]

3 minutes ago, jonathan_dyane said:

On the ring gear if the access is good enough through the starter aperture it might be possible to build the problem teeth up with weld and profile with dremel?

Sadly most of the teeth are problem teeth so that would take about a month...

[jonathan_dyane]

Bad times!

[Talbot]

1 hour ago, wuvvum said:

hoik the engine and gearbox out complete through the bonnet

You would need some fairly serious height capacity to be able to do that.  You'd need to tip the engine backwards by about 45degrees to enable the sump to clear the slam panel while the gearbox rear extension is still clearing the bulkhead.  Once the gearbox has cleared, you then cannot change the "angle of the dangle" easily, so you then have to lift the entire engine and box high enough to clear the front panel.  It's a LOT higher than you expect it to be.  If you're restricted to working with an engine crane, it will be much easier to remove the engine on it's own as it can come up level and then clear the front panel level.

In fact.. given the fairly massive amount of space to work with in this engine bay, that would likely be a more sensible option than trying to remove the gearbox under the car.  Engine out,  change the flywheel ring gear, shove a clutch in it (as it's bound to need one) clean up the engine bay and then back in.  Fresh coolant and a service and you're done.

[wuvvum]

This is true, however that would still entail scrabbling around underneath the car trying to get everything to line up when refitting, rather than putting everything back together outside the car with unlimited space and the ability to wiggle both engine and box as required.

[Talbot]

29 minutes ago, wuvvum said:

scrabbling around underneath the car trying to get everything to line up when refitting

Re-fitting is relatively straightforward.  You suspend the engine so the gearbox input shaft is lined up with the clutch hub and gently pressing on it, then jack one rear wheel slightly off the ground.  Put the gearbox in 1st gear and have someone slowly rotate the wheel while you gently wiggle the engine to get it to engage.  Once it slots on, a couple of bolts to hold it in place and then it's just bolting everything back together.  Much much easier than trying to manhandle a gearbox into position from below and get the clutch splines to drop in.  If you use an engine balancer bar that you can wind back and forth, you should be able to do all of it with minimal struggling.

Unless you can remove the entire front of the car, I really don't think you'll be able to pull the engine and box together.  Not without something significantly larger than an engine crane.

[Tepper]

8 hours ago, Talbot said:

Unless you can remove the entire front of the car, I really don't think you'll be able to pull the engine and box together.  Not without something significantly larger than an engine crane.

If you can remove the front of the car easily enough, it's a nice way of doing things. I've just pulled the engine on an E36 and it was dead easy with the front end off, 11/10 would recommend.

[lanciamatt]

I don't think you can, as wings  wrap round front quite a bit

[Talbot]

On 4/6/2020 at 8:59 PM, wuvvum said:

I assume heating would require an oxy-acetylene setup and my little propane blow torch would be as much use as a fart in a hurricane?

Only just noticed this.

Actually, as you're only looking for 220c-250c, most domestic ovens turned up to maximum will do this.  Gas Mark 9 is apparently 246c, and most electric ovens top out at 250c, so if you max it out and leave the ring in there for about an hour, it'll be very evenly heated and ready to drop straight on to your pre-chilled flywheel.

[wuvvum]

It's been a while...

I've had this up for sale on C&C for a couple of weeks - I've had some interest and a couple of pisstake offers, but no buyer has yet materialised - I had one chap last week who seemed keen but he's found another closer to home.

This evening I decided to order it a new ring gear - just under £50 delivered from Germany.  My reasoning being that if it doesn't sell it will reach the top of the queue one day and I might have a bash at it if I can get someone to give me a hand (it occurred to me that if I were to take the engine out in the road outside my house nobody could say anything, seeing as it's taxed and insured), and if it does sell then the new ring gear is a nice bonus for the buyer.

[NorthernMonkey]

Hnnnng....so much want for this when you first got it and to be honest, nothing much as changed.

[wuvvum]

The ring gear arrived on Saturday morning, having ordered it from Germany on Wednesday night.  Parcels from the UK don't ever get here that quick...  DHL left it with next door as I was away.  Remains to be seen if I'll actually get round to doing anything with it mind...