Master cylinder removal

Post by **cloud** » Fri Dec 25, 2009 5:57 pm

Is it possible to remove the brake master cylinder without removing the torsion bar?? I was thinking of cutting the heads off the bolts (not sure how yet) and then installing new bolts from the other side when reinstalling. Any suggestions are appreciated.

Post by **alex_holden** » Fri Dec 25, 2009 7:14 pm

It's possible to bend the torsion bar out of the way sufficiently to take the bolts out and replace them. Either lever it down using a hefty crowbar and a block of wood as fulcrum (this tends to require three hands), or clamp something across the chassis rails and use a screw clamp to pull on the bar (DTH posted a photo of this technique a while ago).

BTW Morris installed the bolts with the heads on the torsion bar side for a reason and personally I wouldn't reverse them.

Post by **cloud** » Fri Dec 25, 2009 8:22 pm

Thanks Alex,
My Minor is a LHD version so the muffler is in the way of any prying and any clamps that I have are a bit big with muffler. I may take the exhaust system off as it seems easier than removing the torsion bar. What do you think??
Martin

Post by **rayofleamington** » Fri Dec 25, 2009 8:24 pm

reversing the bolts can give you dangerous grooves worn into the torsion bar - if you don't beleve me, you'll be able to find a few at rallies. When installed like this, there may look to be some clearance, but the torsion bar flexes under load...

I've managed bolt removal and refitting using a crowbar on the torsion bar (+block of wood) plenty of times. I only found it difficult once, and that was due to a rotten floor / chassis leg area!

Post by **bmcecosse** » Sat Dec 26, 2009 10:39 am

My bolts are reversed - and no grooves. Just trim off the excess threaded section - if there is any. Makes life SO much easier in future! Yes - I would drop the exhaust and either lever it - or cut the heads if you have new bolts handy.

Post by **aupickup** » Sat Dec 26, 2009 10:45 am

agreed bmc

but shouldnt we be telling the folks the proper way

Post by **bmcecosse** » Sat Dec 26, 2009 10:48 am

That IS a perfectly proper way! It's better than the original, I think - but each to their own.

Post by **aupickup** » Sat Dec 26, 2009 11:05 am

must admit have never found fitting the bolts the correct way any problems any way

Post by **mike.perry** » Sat Dec 26, 2009 11:14 am

I reversed the master cylinder bolts on my Series MM 25+ years ago. I used packing washers under the bolt heads to make sure that the bolts did not touch the torsion bar

Post by **mike.perry** » Sat Dec 26, 2009 11:20 am

but shouldnt we be telling the folks the proper way

There are often alternative ways of doing a job and as long as the methods are safe then I do not see a problem. I doubt very much if it would be marked down in concours!

Post by **aupickup** » Sat Dec 26, 2009 11:45 am

yes there are different ways to doing a job

the right way and the wrong way

ok so lets teach the newbies the txt book way first and when there skills increase they can then do it waht way they want

or shall we rewrite the book

Post by **mike.perry** » Sat Dec 26, 2009 12:09 pm

Assembly was undertaken in the factory in a particular order for the simple reason of ease and speed of construction on the assembly line. In the case of the master cylinder bolts it was obviously easier to stand on the outside of the car, push two bolts through and then fit and tighten the nuts on the inside before fitting the torsion bars.
Also special tools were often used which are not available to the home DIY mechanic who has to find a method using ordinary tools.
I still maintain that there is not necessarily a right and wrong way but a safe alternative way. This also includes using tools supplied in the tool kit. It is a general recommendation that for reasons of safety the issued jack should be substituted for a scissor or trolley jack.
Can you claim to do every job on your car in exactly the method shown in the BMC Workshop Manual?

Post by **rayofleamington** » Sat Dec 26, 2009 4:06 pm

My bolts are reversed - and no grooves.

How many have you checked and what mileage per year do you do?

The bolts were not fitted the correct way "by chance" - they were specially tooled to have thin heads, as the Torsion bar can move under load. The bolt head is much thinner than the nut. If you don't belive it, check a load of cars next time you go to a national rally and you'll find some with grooved torsion bars.

My Minor is a LHD version

Ah - well it seems you've already worked out the solution! I've only done one LHD master cylinder, and had to remove the exhaust.

Post by **bmcecosse** » Sat Dec 26, 2009 4:10 pm

Ray -I simply stated that MY bolts are reversed - and no grooves. I have checked one car - mine - it works ok - can't see why it wouldn't work on them all - IF the excess thread is trimmed off.

Post by **rayofleamington** » Sat Dec 26, 2009 4:22 pm

can't see why it wouldn't work on them all - IF the excess thread is trimmed off.

because the torsion bar moves under load, and that's why they had to make a special thin head on the bolt. (is there an echo in here?)
Thank goodness the guys at Morris could understand good design practise, rather than take chances! ;-)

Again, what kind of mileage do you do per year?

Post by **bmcecosse** » Sat Dec 26, 2009 4:56 pm

Low miles each year - but MANY miles total since the bolts were reversed!

Post by **mike.perry** » Sat Dec 26, 2009 5:33 pm

I have driven the car in excess of 150,000 miles since I reversed my bolts

Post by **bmcecosse** » Sat Dec 26, 2009 5:59 pm

Jings! And STILL the torsion bars soldier on...............

linearaudio · Post by **linearaudio** » Sat Dec 26, 2009 6:18 pm

I'm guessing that the main point is that with nuts rather than the thin bolt head, the clearance doesget minimal as the bar flexes. However it would appear that if you pack the bolt head out or shorten so none protrudes from the standard nut, then there is not an actual problem.
Mine has run 18000 hard miles in 18 months, and no witness marks.

If we are going to get into safe practises, then the whole idea of levering torsion bars around whilst wiggling bolts out strikes me as fraught with peril! I certainly didn't feel very confident doing it, but the alternative "proper" method is far more long-winded!

Post by **bmcecosse** » Sat Dec 26, 2009 6:33 pm

Indeed - with all the 'levering' - you may snag a finger nail - take care!