njc110381 Posted April 15, 2014 Report Share Posted April 15, 2014 I've been out trying to bleed the brakes on my mog today and have stumbled across a bit of a snag... I can't get the bleed screws to shift on the master cylinder. I'm not sure what they're made of (brass maybe?) but it's not very hard. I don't want to force them too hard and snap them. Any ideas how I can get them loose? I did think a bit of heat could help, but being close to seals I don't suppose I could get it that hot anyway? I'm a bit stuck. I get the feeling it's something that could be quite easy to mess up! Quote Link to comment Share on other sites More sharing options...
88b Posted April 15, 2014 Report Share Posted April 15, 2014 Mog ? Morris Minor ? Does it have bleed screws on the master cylinder or are you talking about the slave cylinders on the wheels ? If the bleed nipples are that tight a deep hexagonal socket so as not to round off the bleed nipples is the answer. If it is an old Morris I thought they had the MC under the floor. Quote Link to comment Share on other sites More sharing options...
la bala Posted April 15, 2014 Report Share Posted April 15, 2014 I have taken stubborn bleed nipples out by welding larger nuts over the top of them. Quote Link to comment Share on other sites More sharing options...
Gordon R Posted April 15, 2014 Report Share Posted April 15, 2014 Never heard of bleed nipples on a master cylinder. Slaves and wheel cylinders - yes - but not masters. Make sure your spanner is a tight fit. Slack fit will round them off. Quote Link to comment Share on other sites More sharing options...
bazzab Posted April 16, 2014 Report Share Posted April 16, 2014 Never heard of nipples on master cylinder. THen again never worked on a Moggy. Have had countless seized on wheel cylinders. The answer ive found is a proper brake hose spanner. There like a hex socket almost but with a piece cut out the front. They make a HUGE difference. Ill try and find a pic..... Quote Link to comment Share on other sites More sharing options...
bazzab Posted April 16, 2014 Report Share Posted April 16, 2014 Here ya go. Not a clue who makes these particular ones but you get the idea.. Quote Link to comment Share on other sites More sharing options...
kent Posted April 16, 2014 Report Share Posted April 16, 2014 Unimog? give it a bit of a rub with a small file on a non important bit to find out metal type and try and get some sort of penetrating fluid into those threads first to ease them. I used to remove a lot of things mechanics had snapped off by welding on top of the broken bits so take care and be patient with the fluid and get the right tools. If the vehicle I think it is the new parts are bound to cost Quote Link to comment Share on other sites More sharing options...
Paul223 Posted April 16, 2014 Report Share Posted April 16, 2014 Unimog, yeah I'm sure Neil has mentioned it before. 6 sided socket of the correct size Wire brush it clean and soak in penetrating fluid, heat will be a no no Whilst your working on the brakes ...... If it's on discs have a measure of the brake pads, I have a set sat in my parts cupboard from a few years back when one of my customers had a couple of mogs, your welcome to them, might even have some lever ball joints too, what model is it? Quote Link to comment Share on other sites More sharing options...
njc110381 Posted April 16, 2014 Author Report Share Posted April 16, 2014 Some great advice there, thanks. It's a 1979 Unimog 406.121. I've never seen bleed nipples on a master cylinder either but this thing has two, one for the main circuit and one for the backup should the first fail! I've already started to give them a good soak in Plusgas. Strangely the ones on the wheel end move easily. I suppose they're probably the ones that have been used the most but is is confusing me a little to know that the ones under cover in the dry are stuck whilst the ones out at the dirty end are ok! This thing hasn't had a very full service history. At 30+ years old there are a few parts on there that I'm not sure have ever been done. Certainly not since it was imported about ten years ago. I serviced the fuel filters yesterday and the pre filter looked like a solid mass of wet mud and the first felt filter was the same... Hey, it might go a bit faster now?! Paul... Thanks for that. Unless we're going back some time they most likely fitted a square cab of some sort, but if they do fit then I would be most grateful of anything you have. Let me know what you want for them. Quote Link to comment Share on other sites More sharing options...
Paul223 Posted April 16, 2014 Report Share Posted April 16, 2014 Some great advice there, thanks. It's a 1979 Unimog 406.121. I've never seen bleed nipples on a master cylinder either but this thing has two, one for the main circuit and one for the backup should the first fail! I've already started to give them a good soak in Plusgas. Strangely the ones on the wheel end move easily. I suppose they're probably the ones that have been used the most but is is confusing me a little to know that the ones under cover in the dry are stuck whilst the ones out at the dirty end are ok! This thing hasn't had a very full service history. At 30+ years old there are a few parts on there that I'm not sure have ever been done. Certainly not since it was imported about ten years ago. I serviced the fuel filters yesterday and the pre filter looked like a solid mass of wet mud and the first felt filter was the same... Hey, it might go a bit faster now?! Paul... Thanks for that. Unless we're going back some time they most likely fitted a square cab of some sort, but if they do fit then I would be most grateful of anything you have. Let me know what you want for them. They were to fit a 1979 big one with a square cab, can't remember model number but it'll come to me (Not the rounded cab) fitted with the om352 and om366 engines, I'll measure them. Must be ten years since I last worked on a mog, very well engineered, very tight to work on! I've done just about everything there is to do on them from servicing to full engine rebuilds, clutches, even had to strip the bell housing adapter out of one to weld it up (cast) as it had snapped around the mount, cab off job! Quote Link to comment Share on other sites More sharing options...
Paul223 Posted April 16, 2014 Report Share Posted April 16, 2014 Pads merc no A 002 420 14 20 Rod end merc no A 000 996 55 45 Pads are approx 150mm x 80mm Quote Link to comment Share on other sites More sharing options...
Paul223 Posted April 16, 2014 Report Share Posted April 16, 2014 U1150 & U1250 Quote Link to comment Share on other sites More sharing options...
Paul223 Posted April 16, 2014 Report Share Posted April 16, 2014 Let us know how you get on with a six sided socket, if it still feels like it wants to round I have another tip to deal with it Quote Link to comment Share on other sites More sharing options...
njc110381 Posted April 16, 2014 Author Report Share Posted April 16, 2014 I'll look up the part codes and see if they match. I have a feeling they may do as I think they share the same axles. Quote Link to comment Share on other sites More sharing options...
saddler Posted April 16, 2014 Report Share Posted April 16, 2014 Was doing the same thing on my car last week, sort of The penetrating oil never worked on one of the bleed nipples. Was told that the best way to apply heat without risking damaging anything was to SLOWLY pour a kettle of boiled water onto the stuck nipple/area around it. May be worth a try Quote Link to comment Share on other sites More sharing options...
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