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MG Midget and Sprite Technical - Gripping Brake Pipe

I've got to replace a rear wheel cylinder, and I cannot turn the 10mm nut on the pipe union without the pipe turning too. It's a hard steel pipe all the way, not flexible.

I've sprayed it with penetrating oil, but no movement yet.

Has anyone found a way of gripping the pipe without damaging it?
Nick and Cherry Scoop

Can you not free the other end first so that it allows it some freedom to turn? If you can then turn the nut and pipe togther even a little that takes the clamping pressure off the assembly and may free the pipe.
Graeme W

Nick,
I had this recently and I held the bent section of the pipe sandwiched between a couple of small squares of wood offcut held together with my hand whilst the other applied wiggly motion to the spanner. My theory was I could feel the amount of stress I was exerting on the pipe in the vain hope that I wouldn't bend it. I didn't (much)and a short sharp application of force finally freed the nut.
Matt1275

You could TRY gripping it tightish with mole grips using a coarse emery cloth to add 'gription' between the jaws

Not hard enough to crush the pipe just hard enough for the emery to grip it as you turn

I hope you are using something like Plus-Gas rather than WD40 Nick, WD doesnt actually work on the thready bits

Or there will be a new crosspipe needed in Paradise :(
bill l

I would be more concerned about screwing the nipple off (Sorry Vicar, tech term!)
Graeme W

Hi Nick,
I have always struggled to save brake pipes once they get to the stage yours are at.
It usually ends in getting a new pipe as Bill suggests.
If it is that corroded/seized then how much more damage are you going to do to it getting it off?
A new set of pipes is £55 and you get a complete set, so you have spares for the rest of the car when you need to work on the other brakes.
The MOT man will be pleased to see new bits on the car come MOT time too (well, mine is).

Dave
Dave Brown

Thanks All. Trouble is, I'm trying to sneak it off and on while keeping the whole system fully charged. So trying to undo at the three-way as Graeme suggests is only a maybe.

Matt - I've tried yours just now, with big bits of wood that gripped the two bends in the pipe. But no joy.

Bill - I tried gripping it gingerly, but I didn't think of emery. I will go out and do that now . . . . . .

. . . . . then order a new crosspiece.

By the way, the cylinder appears to be seized. I took the drum off and got Laura to apply pressure to the pedal, and nothing moved. I was expecting to see fluid everywhere, after the MOT showed up no braking at all on that wheel.

Is seizing common?
Nick and Cherry Scoop

Thanks Dave.

I will let you know in about ten minutes.

Now that you've helped me out, I can admit that this is my Morris, not the Frog, and I need her on the road!
Nick and Cherry Scoop

Flexi clogging up inside maybe?

Fluid not going down all the way to the end?

Sounds like fun, not.

Guess who has to take his handbrake off the tunnel in order to TRY to weld the backing for the bracket

Hap hap happy days
bill l

No joy with the mole grips and emery. I expect I'm not being bold enough - having no replacement cross-piece to hand.

Anyway, I've had to sling it all back together again temporarily, because she's standing in the middle of the front yard. Schoolboy error.

Moral - don't start a piece of work in a place where you can't leave the car standing for a week.

Anyway, while the pipes are winging their way to me, we will be travelling north to Alfreton with Cherry's cylinder head. I shall report back
Nick and Cherry Scoop

Fluid not getting there is a good call, Bill. Because the union to the cylinder is not tight, but it ain't leaking.

I put a cramp on the cylinder and pressed the brake pedal just to check, but everything's dry.

I will take Dave's advice and scrape together £55.
Nick and Cherry Scoop

Give Peter my regards Nick

and enjoy the experience, I love that workshop
bill l

by the by Nick

we like helping Moggy Minors too
bill l

Thanks Bill. I'll let you know what happens at Alfreton.
Nick and Cherry Scoop

Nick, a variation on Bill's Mole grips and emery, is to stick a turn or two of fabric Elastoplast around the thing being gripped, rather than emery, before attaching the Moles. Once compressed by the Mole grips it is surprising how firmly the sticky plaster sticks.

The other thing that will help release the tube nut from the tube without damage is to heat it with a small flamed gas blow lamp. The ones sold for doing crème brûlée are ideal and wont damage the bits you intend to heat, or set fire to the car.
Guy Weller

Thanks, Guy. I've sent for the bits, but I still have to get the nut turning, and I'm sure Laura has a crème brûlée torch.

Is it OK to boil the brake fluid? I am a child in such matters, and so - flame on the nut? Flame near but not touching?
Nick and Cherry Scoop

"a child in such matters"
How really wonderful that must be. My granddaughter is just over 13 months, Every day bizarre events just happen. With no prior warning or experience, new experiences and things continually just happen or appear around her. It must be just amazing, one thing after another. She is continually hyped up and just buzzing with excitement.

Today she met a real live chicken, much the same size as herself. She had never seen a real one before, just cartoon style pictures in books. And then suddenly this thing appears before her. Without hesitation she clearly shrieked "chicken" (never having said the word in full before) rushed after it (she has been walking for all of two weeks now) and rugby tackled the thing, flinging both arms around it in a hug of feathers and squawks. It was so funny to watch!
Guy Weller

Well, I did destroy the pipe, but only once it was off the car. The inner end came apart easily - I suppose because of its location in the middle of the car with oil flying around, rather than on the wheel with water and dust its nearest companions.

Now the bleed nipple won't work. Actually, how DO they work? Is the cone supposed to have a hole in its end?
Nick and Cherry Scoop

Yes, there should be a small hole there. You may need to poke it with a thin wire or similar.


Dave O'Neill 2

Thanks Dave. I shall look again.
Nick and Cherry Scoop

Oh - one other thing: is it easy to tell the difference between Dot 4 and Dot 5?

Or rather, how can I tell what I've got in the system? (haven't had the Morris long, and haven't had to top up).
Nick and Cherry Scoop

Nick,
surely it's more likely you have DOT 3 or DOT 4 rather than DOT 5 (silicone)

the only DOT 5 I've seen is a vivid purplely-blue colour

I've no idea how you'd tell the difference between DOT 3 and 4, they will mix so if you're unsure top up with DOT 4 as it has the higher boiling point

as the car is new to you you could try looking back at any history or receipts you got with the car to see what was bought

BTW you can get rubber nipple covers for all the grease nipples and bleed nipples, protects from muck getting in or blocking, I've had these on my car for a few years now and have only lost one - http://www.ebay.co.uk/itm/GREASE-NIPPLE-COVERS-DUST-CAPS-BLEED-SCREW-CAPS-x-20-/151333004918?pt=LH_DefaultDomain_3&hash=item233c266676
Nigel Atkins

it is a good idea to flush the fluid completely so that it is all new from the master to the cylinders, to get rid of all the old (and water logged) fluid

in that case, any concerns about whether it is DOT 3 or 4 in there now, should be ameliorated


N

Norm Kerr

Nick,
sorry I thought it was a case of topping up, if it's a refill then as Norm has put
Nigel Atkins

Well, I've never used silicone, and when I looked at the reservoir I noticed that the fluid was milky - actually yellowish. I wondered if silicone fluid was that colour.

Norm, I think I will flush the whole thing through as you suggest, with new Dot 4 fluid. Lots of it.

I suppose I could take a fingerful of what's there, and see if it strips the paint off my Frogeye (up for a respray).
Nick and Cherry Scoop

Nick,
if the Moggie has that reservoir under the floor made of monkey metal where you can't unscrew the cap without deforming it then it may be that the brake fluid is very old

most car owners forget about or ignore changing the brake fluid

if the fluid has a lot of water in it you might need to leave it the paint to work

I was wondering about the use of Super DOT 4/5.1
Nigel Atkins

If its been in for yonks I'd almost run two systems worth through it to flush out absolutely everything. Dot 4 isn't pricy and it always seems to take me two good goes with a drive in the middle to get rid of the last remnants of whatever is in the pipes that shouldn't be. Eazibleed is your friend (provided you screw the cap on properly!)My biggest bugbear is that all my nipples seem to be different sizes and my usual tool is too big to fit the smallest one................
Matt1275

Nick,

While Nigel is correct about DOT 5 being purple, it is not true when it is old. When it is old, it is more yellow. Seeing if your current brake fluid will strip paint may be a valid test. Given that it is milky, it certainly needs a flush.

Charley
C R Huff

that's interesting Charley about the change of colour on silicone and perhaps a bit worrying as it's supposed to be for long term use (well storage at least)

I'm with Matt DOT 4 isn't dear use it for a thorough flush
Nigel Atkins

Thanks all.

What's a sensible method for flushing?
Nick and Cherry Scoop

You need to establish what type of fluid you have first, as Dot3/4 and silicone are not compatible.
Dave O'Neill 2

Europarts (and others) sell coloured Dot4. It's very useful for a complete flush as you can clearly see when the new stuff comes through as it seems to stay unmixed as it passes down the pipe. It's more expensive than standard but takes the guesswork out of it.

Be very careful with Easibleed! Cover the top of the reservoir with a towel or old cloth because if that cap leaks or the pipe pulls out you could potentially finish up with a respray job!
Graeme W

OK - two questions :-

1. Is there any other way of telling which fluid I have? Smell, taste, purchase of expensive measuring equipment, securing the services of a dowser, holding a seance, etc etc?

2. Would you do a big empty-out first, or just pour the new in on top of the old?
Nick and Cherry Scoop

PS :- I prefer the beautiful assistant to the eazibleed. The cap always leaks on mine.
Nick and Cherry Scoop

As Charley said, testing your current fluid on some paint is probably the easiest way of testing it.

Unless you want to replace all of the seals in the master and slave cylinders, you want to stay with the same type of fluid that you already have.
Dave O'Neill 2

Nick also had the idea himself earlier of testing against paint

again I'd say if it's old and watery then leave it on the paint for a while

I'd have some water around in case of accidents (don't ask how I know)

personally with all the rubbish rubber about I'd be very reluctant to replace just seals
Nigel Atkins

When I flushed mine out recently I stuck the easibleed on empty and opened the back left bleed nipple and drained the lot off until it was just blowing air, then filled up the master cylinder and did the same again draining off a bit of each wheel and then refilled and bled again as normal. Despaired a bit when I still had a soft pedal but another couple of bleeds after a god run and all was well. When I first got the car I just assumed it was dot 4 out of ignorance and filled up with that so can't help on identification.
Matt1275

I've heard of using alcohol as a flush, but I think that was just for the lines. As Dave said, usually the rest of the system is rebuilt or replaced when making the change. I think you can get by with changing from DOT 3 to 4, or the other way around, without disassembly. But, it is not recommended when doing a switch to or from DOT 5. Beyond the paint test, I don't know how to tell what you have. I would think they would smell differently, but I've not checked it.

Charley
C R Huff

Well, I'm just going to do it. I called the previous owner, who thought it was almost certainly dot 4, and I asked my local mechanic, who thinks a little dot 5 in a dot 4 set-up will not be a problem. And he gave me a gallon of dot 4. So there won't be any niminy-piminy eco-flushing at this end.

Let's see what happens.
Nick and Cherry Scoop

This thread was discussed between 30/06/2014 and 09/07/2014

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.