thermostat and water pump assembly tips?

[xpress]

Hi can anyone chip in a few tips before I take off the state housing? Its not leaking. Top hose gets warm. Was going to put state in/change state since I have never opened it before. I have a new gasket but no housing. Should I leave it alone for now and just do water pump (which is leaking)?

Also .. are the mg stat housings with plug for switch good to use with no problems?

Do the studs sometimes get stuck in the block do they twist out with pliers?

Also when you remove water pump and dynamo does it affect belt tension or is that adjusted by some other pulley tensioner?

Lastly, does the fan come off ok?

Any other course of action things to think about?

Thanks all!

[chrisryder]

fan belt tension is affected by dynamo (or alternator if you've got one). effectively taking the water pump off won't affect tension, but you probably won't be able to take the pump off with the belt at normal running tension. you can sometimes take the pump off with fan blades still attached. one less thing to take off and loose the bolts for! it is easier to get to the water pump bolts with the fan and pulley (fan retains the pulley) removed. you shouldn't have a problem getting the fan bolts out. they're 7/16 heads by the way.

if you're draining the system, it could be worth while taking the thermostat cover off too. but if you remove the top hose you should be able to ascertain if a thermostat is in there with the aid of a torch or a small finger!

thermostat housing studs often rust into the head.

you'll be lucky to get the thermostat housing off without destroying it. if it comes off easy then it probably has been off recently!

no idea about the use of mg housings. the orientation is the most important factor!

[xpress]

Why did they use studs and not bolts? Do you work the studs out with plusgas penetrating fluid and pliers and extractors easy outs if bad and leave well alone if they seem ok thread wise to be reused?

[xpress]

Also would the stat housing come off without draining much coolant when coolant is in the block since it's at the top?

[chrisryder]

if they look ok leave them be. sometimes as you undo the nuts, the rust on the exposed thread at the top cause the nut to lock, and then you end up winding the bolt out. in that case, you're lucky as it makes the housing removal easier!

plus gas down the threads is a good idea. and maybe even plus gas down the stud holes in the housing before removing to help free it up.

regards coolant level, you shouldn't have to drain much, but i'd certainly drain a little. at least so that the water level is below the top of the core when viewed through the rad cap.

[bmcecosse]

Don't touch the thermostat - just swap the water pump if it's leaking - but are you sure it's not the daft wee bypass hose that's leaking ? Fit a new one anyway - and NOT the useless corrugated one !

[xpress]

If theres no play in the pump bearing is it best to keep going with the old water pump and a new gasket ie are old pumps better than modern ones or are they ok to swap? I guess I could leave the fan blade on clean and change gasket and change to silicon bypass hose?

[xpress]

been busy taking the rad holding bolts off as you will read below but i tightened up the top clip on the bypass hose and put her back together for now, will flush with water and see if this solves the leak!

a few good hours on her today, i was taking the rad out and testing a spare rad that i have here. when taking a top left o/s front bolt out, it sheared off! did go carefully, but didn't use any fluid and didn't notice that it wouldn't turn, i expect the metal was so fatigued it just turned off and sheared. a couple of the other bolts on the rads seemed to be different sizes? what size are the rad bolts supposed to be? i guess i can drill out this stud with a very small drill bit and then punch it out with a metal punch since it's exposed on the other side. any thoughts?

also i have a good spare rad, but i opened up the drain tap, didn't know that it doesn't come out all the way, and then the handle came off, i think it's delicate, only held on with a few small bits of metal, would a smear of liquid metal or a good glue (no more nails or something) work to attach it back on? so at the moment it's stuck at the "drain" position lol. so this drain tap key doesn't come all the way out? has anyone removed the brake pipe union that holds this drain tap key to swap it for another one, or are they sealed up maybe with a rubber seal on the unexposed side? it's certainly a voyage of discovery with old cars lol.

the thermostat studs, most of them look ok, one looks a bit rusty, if the nuts are taken off, should the thermostat slip off these studs? or is it the case that it gets rusted shut to these studs? has anyone removed the studs from the block? how far in are they? another drilling out job if they don't turn out with pliers?

i had a look at the dynamo, there's a big nut at the bottom and one at the top, and another nut at the back at the top, are there three in total? then it's the water pump to take off? i guess if these bolts are rusted, they may possibly shear off in the block if it's not been out in ages, and then drilling out, helicoil possibly needed?

any thoughts? thanks.

[chrisryder]

that was a few questions!

not sure what size the rad bolts should be. i tapped the threads out to M8 and used short M8 bolts (i had loads to hand!). be carefull if drilling or tapping (or both) as the other side is exposed, but there's only a short gap before you hit the core of the rad. if you drill a hole in that you're stuffed.

with your drain tap, the whole tap should be able to unbolt from the rad, and new taps are available. i wouldn't try no nails or anything, the water is under pressue in there so it'd have to be strong!

i wouldn't have gone for a silicone bypass hose, just a length of normal heater hose would have done. anything but the compressible ones! you can only fit a solid hose if you have the head off or the water pump off. that's why people fit the compressible ones.

thermostat housings always seem to rust onto the studs. if you can't get that rusty stud out by running two nuts down it, and locking the nuts together with two spanners (or a spanner and a socket) and 'undoing' the bottom nut. i'd be tempted to leave it in and rub the rust off with some sand paper, then smear all of the studs with plenty of grease before refitting.

you also asked how far the studs go in. they're about 1/2 an inch in if i recall.

those 3 bolts you've found are the only three holding the dynamo on. that 'big nut at the bottom' should be bolted through a slotted plate. if you loosen the big nut (and the two top nut and bolts a little) you should be able to press the dynamo down to loosen the fan belt. this is how you change the fan belt or adjust it. when re-fitting, you should have the belt tight enough that you can just about turn the fan blades by hand. if you can't it's too tight, if it's really easy, it's too loose.

the top bolt at the front of the dynamo bolts though a flange on the water pump. so if you remove the pump you will need to remove that top bolt too.

i think that's everything!

[xpress]

thanks for your answers! i will have a think through these, was finding it hard to understand about the two nuts on the thermostat housing studs, is that to trap one nut against another and then turn the studs out with a socket? also, when you say you ran some sandpaper over something to get rid of the rust, did you mean the other side of the thermostat housing and you reused your thermostat housing? i guess to avoid rust you could copper grease the thermostat housing before fitting a new gasket? or maybe some light smear of hylomar, then attach the gasket, then fit this to a cleaned up water pump face? if the studs come out in one piece maybe it's a good idea to replace them with new studs?

i was surprised that the bolt broke in the rad, have you had bolts break in there? I will order some new bolts for it, i copper greased the couple i have and they're going in and out of the threads nicely now.

i took a look through the pipe at the thermostat, there's definitely one in there. it may either be stuck open or working just fine. i know that you won't be able to see a difference in it if it's stuck open or shut because it's just a spring inside the assembly that differs during being open and shut. the top and bottom rad hose has been getting hot so it's obviously working.

the tap on the spare radiator is fine, it's just the handle that's come off, it's held on normally by round serrated very thin bits of metal to the end of the brake union, i think a little smear of glue would hold it on better, it's just the little tap handle that came off. when glued back on i can turn it and shut the tap and open it again. it's open at the moment.

i ran a light under the dynamo, and beside the oil filter housing, and i finally traced this leak, it's definitely running down to the front of the sump, centrally, dripping slowly to the floor. it's coming from the bottom of the water pump definitely. i thought it might be from the bypass hose but i nipped it up earlier and it's still bone dry. it's only a slow leak but the water pump will have to come off.

[chrisryder]

if you get the stat out, the best way to test it is to put it in a mug of boiling water. the boiling water should open the stat, and as it cools the stat will close. if you have a thermometer you can measure the water temp and determine what temp it closes.

if the studs come out, new ones are always a good idea. i'd still put lots of grease on the studs before putting the housing on them. i wouldn't grease the housing. the sand-papering was with regards rubbing the rust off the rusty studs.

with regards getting the stud out. trap the two nuts against each other. but dont turn it with a socket as the socket will just undo the top nut from the bottom one. get a spanner and undo the BOTTOM nut. this will tighten it up to the top nut and hopefully turn the stud out. dont force it too much or you will probably break the stud.

[xpress]

thanks for your help. funny thing, i am just putting up with the slight drip at the moment, and i expected to have to bleed the cooling system, but the morris doesn't seem to need it. i could hear a bit of air trickling about when i put it back in the garage, but i felt the rad, it feels hot and the head feels warm to the touch. top hose warm, bottom hose warm. does the morris bleed itself with the heater valve open but the heater not on, and via the hose from the rad? am i right in thinking the morris doesn't really need bleeding?

[chrisryder]

i've never 'bled' too much. does your heater feel hot?

quite often i squeeze the bottom and top hoses alternately, and then together, to slosh any air out.

ideally you should take the hose off the heater tap, hold it up high (as high as it'll go) shove a funnel in the end and pour water in. then pull the funnel out and stick your thumb over the end. then shove the hose back on the heater tap as quick as you can to avoid getting too much water everywhere!

[bmcecosse]

Just fill up and run the engine -I have NEVER had to bleed a Minor or Mini engine........