Brakes "Whooshing"

Post by **Packedup** » Wed Jun 18, 2008 8:34 pm

Tried bleeding my brakes again today, with no success. I noticed a whooshing coming from around the master/ pipe to the rear cylinders - I take it this is not normal!?

I managed to get a bit of a pedal, then after leaving it a while there was none again. Am I right in thinking it's time to invest in a new master? And if so, I've been told the pattern ones don't work with discs - Is that definitely the case, as I might want to stick discs on sometime and would rather not have to change masters again if I do!

Post by **Kevin** » Wed Jun 18, 2008 8:37 pm

I think the first thing to do is have a look around the master cylinder you really don't wont to be driving a car around with an iffy one.

Post by **Packedup** » Wed Jun 18, 2008 8:46 pm

Well, this master had been leaking (became apparent when removed from the donor car), but I rebuilt it with new seals. The noise just sounds plain wrong though. You're right, I don't waqnt dodgy brakes! Time to find more cash for this "cheap quick" rebuild on the pickup I suppose...

Post by **bmcecosse** » Wed Jun 18, 2008 11:44 pm

Have the tried just gravity bleeding ? Works every time for me. And are you sure you got the seals in the master in the right order? Any master will work with discs (if you must!) - but with them all - the little residual pressure seal must be removed or the pads will drag on the discs.

Post by **Packedup** » Thu Jun 19, 2008 12:45 am

Tried everything (other than pressure bleeding, and some form of human sacrifice) - The whoosh worries me, as does not being able to get much of a pedal, and continually seeing bubbles in the bleed tube. If I just crack the nipples open nothing appears, no air, no fluid. I was putting this down to the master being so low in the car, but if it normally works I guess there's something else fouled up somewhere. Much as I don't want to part with more cash I haven't really got, brakes are on the important side IMO, so it really is looking like new master time

Post by **bmcecosse** » Thu Jun 19, 2008 8:08 am

Does sound odd - have you tried 'pressure bleeding' - where a worthy assistant pumps up the brakes as hard as possible - and then you open and shut the nipple - just a short burst ? Other tip may be to adjust all the cylinders up hard - so the wheels don't turn. And usually you would start at the furtheste point - but may just be worth trying the nearest point (driver front) first just to get good bubble-free oil in the master. Good luck mate - I can see how soul destroying this must be after all your hard efforts over the last few days.

Post by **Dean** » Thu Jun 19, 2008 11:22 am

If it is air then there must be a leak somewhere? I'm working on the theory air will rise to the highest point eventually, so if all seals are good in the master you may have a dodgy connection in your pipework or a leak at the first front or first rear wheel cylinder? Just a thought. I'm doing my master cylinder at the moment on my moggy and you really have my sympathy..... it's a fiddly one!

Post by **polo2k** » Thu Jun 19, 2008 11:39 am

dont forget that if you undo the rear brake union (f/r pipe out of the mounting at the rear of the car then you will be able to get a lot more room

also if you have a tyle lever with a reflec curve in it then you can use this to bend the tortion bar out of the way ant its a lot less likly to slip and hurt you. The first time I took a tortion bar off on mog I got the tention wrong and somthing slipped and the front anchor of the tortion bar twisted and broke my wrist. learnt my lesson on that though!

Post by **Packedup** » Thu Jun 19, 2008 12:22 pm

When I put the master in I fitted the rear pipe first, and I suspect when I come to redo it I'll do the same again

As for the torsion bar... Well, when putting the master in a long time ago, the bolts went from the inside - And that's how they went again this time, and how they will go yet again tomorrow! A bit of threadlock should keep things good in the unlikely event they somehow come loose, and the thought of bending or dropping the torsion bar doesn't appeal, I'm trying to put this together, not take it apart!

I'm just hoping the new master will actually work, and I can get it all bled through and actually have brakes after all this. It's been an unexpected expense (the master came off a car that had been in daily use till a couple of weeks ago) and time consumer that I really didn't need. Still, the clutch is now free, the suspension is all on (needs nipping up once everything's on and it's settled to normal height), the front lights work... There's only some work on the rear frame (aftermarket angle iron thing), bit of welding, spraying and interior to do and it's pretty much finished. If I can find the funds and the weather stays good there's a high chance it can be nearly done by the end of the week. I just hope there's no more nasties lurking, as I really need this done very very soon!

Post by **Dean** » Thu Jun 19, 2008 12:46 pm

polo2k wrote:also if you have a tyle lever with a reflec curve in it then you can use this to bend the tortion bar out of the way ant its a lot less likly to slip and hurt you. The first time I took a tortion bar off on mog I got the tention wrong and somthing slipped and the front anchor of the tortion bar twisted and broke my wrist. learnt my lesson on that though!

I simply cut through the bolts with a junior hacksaw.... ok I lie it took two hours to take off and just over £3 to replace to replace the bolts. But set this against resetting or bending my torsion bar it seemed a small price to pay.

They will be going back in reversed!

Post by **bmcecosse** » Thu Jun 19, 2008 7:37 pm

Just make sure the bolts are not so long that they touch the torsion bar - allowing for it to move about slightly under load! If there is any danger - either put washers under the head of the bolts - or cut a slice off.

Post by **Packedup** » Thu Jun 19, 2008 9:35 pm

When I first fitted the master oh so long ago, I used some thick washers on the bolts to keep the ends off the torsion bars - Will be doing the same again

Post by **Dean** » Thu Jun 19, 2008 10:15 pm

bmcecosse wrote:Just make sure the bolts are not so long that they touch the torsion bar - allowing for it to move about slightly under load! If there is any danger - either put washers under the head of the bolts - or cut a slice off.

Thank you, good advice.

Post by **rayofleamington** » Mon Jun 23, 2008 8:40 pm

The torsion bar is made of spring steel otherwise it wouldn't work properly, so bending it out of the way isn't going to hurt it. Putting the bolts the correct way round is the only robust solution and takes much less time than cutting the nuts down to be thinner etc...
I prefer to use a car tyre lever and a jack, as the curved end of the lever hooks the torsion bar and the flat edge sits securely on a jack. This allows bolt replacement in less than 10 minutes (I certainly wouldn't spend the time to cut through them!) In the past I've used a crow bar and levered it by hand but that's been more fiddly.

The first time I took a tortion bar off on mog I got the tention wrong and somthing slipped

General rule for any dismantling or rebuilding - assume something will slip or move and'or the jack will fall over. If that happens then make sure you are not in the way of what happens next!
Axle stands are less likely to fall over, however it does still happen (I've managed it). When under a car that is raised up I use a stack of spare wheels to make sure that the car has something to land on that isn't me!

Anyway - as for the whooshing sound....
Some of the seal kits available from our lovely suppliers are not good. One typical error is the missing breather hole from the boot! Therefore when you press the pedal, the boot will pressurise and leak around the flange - maybe that's your whoosh??

If the m/c was leaking then it's likely that the bore was corroded by the secondary seal - if so, then a seal kit won't fix it.