Another brake question...

[geoberni]

So as Basil (SII) hasn't really moved far in the last 18 months, I thought I'd take an overdue look at the brakes.

As the Front drums are 8" internal surface diameter, I'm assuming that like several other things, when he was rebuild some years ago he had the latter Minor 1000 front brakes fitted.

Can anyone confirm these are just the standard latter front brakes and not some other common brake upgrade/substitute?

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I'm guessing the drums were new not that many years ago, since they're in very good condition, with the clear marking of some part number...

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Thanks

[ManyMinors]

Those do indeed look like standard late Minor 1000 brakes
Original drums will all have "MOWOG" cast into them

[geoberni]

Thanks for confirming what I had hoped was the case.
Basil's brakes are really seized up, so I'm going to replace all the slave cylinders with ones that have been suitably 'Red Greased'.

While I'm doing that, since the system is being broken into, I'm going to rotate his Servo, which is basically mounted upside down, thus the brakes have always been a bit spongy in the past as it's impossible to get all the air out with the servo that way around....

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All instruction leaflets for fitting a Servo clearly state that it 'should' (I would say must) be fitted with the white Air Control Valve mounted low to allow bleeding the air out

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So the numpty that fitted Basil's did the complete opposite.

[ManyMinors]

Why do people think they even need a servo

[geoberni]

Why do people think they even need a servo

I wouldn't have bothered, from the looks of it, it was added when the car was rebuilt about 20+ years ago. There's nothing to indicate Basil was ever 'off the road' for a long period, but from what I've pieced together it was about 1999 when some significant work was done. That's presumably when the 8" Drums were fitted, along with a few other later Minor bits, like the rear wings.

I suppose people go for what they think are worthwhile improvements; Brake Servos do figure high on many lists.
See this article for example: https://magazine.heritagepartscentre.co ... ar-brakes/

But since it's there, I may as well get it installed correctly...

[Flywheel]

Thanks for confirming what I had hoped was the case.
Basil's brakes are really seized up, so I'm going to replace all the slave cylinders with ones that have been suitably 'Red Greased'.

While I'm doing that, since the system is being broken into, I'm going to rotate his Servo, which is basically mounted upside down, thus the brakes have always been a bit spongy in the past as it's impossible to get all the air out with the servo that way around....
20170906_112602A.jpg

All instruction leaflets for fitting a Servo clearly state that it 'should' (I would say must) be fitted with the white Air Control Valve mounted low to allow bleeding the air out servo.JPG
So the numpty that fitted Basil's did the complete opposite.

Hi Geoberni, it Looks like the same servo fitter has struck again. Have you any instructions or tips that you could pass onto me please?

Any hints, tips or wrinkles would be much appreciated. Many thanks Jonnie.

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[MCYorks]

Basil's brakes are really seized up, so I'm going to replace all the slave cylinders with ones that have been suitably 'Red Greased'.

The wheel cylinders do seem to be a weak point. The trouble is the O-ring only seals when the piston is fully retracted. So, whenever you're braking there's the potential for dirt and moisture to work their way into the cylinder. A good coating of red rubber grease helps keep most of the moisture out, but it's a pity BMC didn't use a better type of seal. Still, at least new cylinders are reasonably cheap these days

[geoberni]

Hi Geoberni, it Looks like the same servo fitter has struck again. Have you any instructions or tips that you could pass onto me please?

Any hints, tips or wrinkles would be much appreciated. Many thanks Jonnie.

The key influencer will be if your servo is 2 or 3 bolt fixing.
Luckily, Basil's is 2 bolt so hopefully will be a simple rotate by 180 degrees, just requiring the feed pipe from the Master Cylinder to be rerouted to the opposite side. I'm hoping the pipework is flexible enough to allow some gentle hand bending. It does look as though it was originally hand bent, given the way it currently lies.

I shall post on here the end result, hopefully next week. My replacement cylinders are currently sat in my local Parcel Force depot (since 01:16 this morning) so I'm guessing ESM didn't pay for Saturday delivery , thus it'll be Tuesday before I get them....

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[Flywheel]

Hi Geoberni, it Looks like the same servo fitter has struck again. Have you any instructions or tips that you could pass onto me please?

Any hints, tips or wrinkles would be much appreciated. Many thanks Jonnie.

The key influencer will be if your servo is 2 or 3 bolt fixing.
Luckily, Basil's is 2 bolt so hopefully will be a simple rotate by 180 degrees, just requiring the feed pipe from the Master Cylinder to be rerouted to the opposite side. I'm hoping the pipework is flexible enough to allow some gentle hand bending. It does look as though it was originally hand bent, given the way it currently lies.

I shall post on here the end result, hopefully next week. My replacement cylinders are currently sat in my local Parcel Force depot (since 01:16 this morning) so I'm guessing ESM didn't pay for Saturday delivery , thus it'll be Tuesday before I get them....


servo 1.JPG

The servo fitted to my traveller is the two stud fixing. However i've noticed that its been mounted forward to allow for a large windscreen washer bottle. It does seem a bit squashed up.

I know that i'll need to move the washer bottle over to the other side of the engine bay to gain more room.

May i also ask you? If i need to disconnect the hydraulic copper pipes, to hand bend them into the new shape. Should i bleed the brakes when completed with the engine running? Or is that not required?

Hopefully your replacement cylinders will turn up, its a pity you didn't get them today, flipping frustrating.

Thanks again for your help, and diagrams. Please keep us posted.

Regards Jonnie.

[geoberni]

Hi Jonnie
Brakes are bled normally.
Here's a couple of the many links to the installation manual for the servo.
www.scparts.co.uk/pdf/533613.pdf
https://mossmotors.com/media/instructions/981-173.pdf
They both say:

In a convenient position, preferably at the highest point in the vacuum hose run, an In line non-return valve is advisable on high performance vehicles.

So I wonder why there's a NRV on a Minor....

The issue of being incorrectly mounted is not that unusual, this video is from a guy correcting a poor installation.
If you look at the comments, I asked him why he doesn't have a U bend in the line as a Fuel Trap and he replies

....don't recall that being in the original Girling Lockheed notes

I've got the AP/Lockheed instructions that were in the documents I got with Basil, and they say there's supposed to be one.....
https://www.youtube.com/watch?v=7-xPLRbDiDw

[Flywheel]

Hi Geoberni, thanks for passing your information on to me.

As a recent Morris owner I had no idea this was a problem. Surely the people who fit these as part of an upgrade, take the time and trouble to read the instructions. The braking system after all is 'safety critical' isn't it!!! Blimey.

I'll certainly have a look through everything. I'm very grateful to you for your time, trouble and patience.

Thanks again, and apologies for my late reply.

Jonnie.

[jagnut66]

Hi,
You could relocate the washer bottle to the passenger side bulkhead, creating much more space for tightening up (or in the future undoing) the servo mounting nuts and brake pipes.
Best wishes,
Mike.

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[Flywheel]

Hi Mike, thanks for the suggestion.

Cheers. Jonnie.

[geoberni]

Have you any instructions or tips that you could pass onto me please?
Any hints, tips or wrinkles would be much appreciated. Many thanks Jonnie.

So, time for an update on getting the Servo fitted correctly.
I thought I'd do this before changing all the wheel cylinders. I can easily work under the bonnet in the garage, there's more room to work on wheels/brakes outside when the weather is more reliable.

It didn't take long to disconnect the 2 brake lines and the vacuum hose.
The plan was to see if it was simply a case of rotating 180 deg.

it was evident from this view that the mounting plate was barely at around 5 deg tilt, whereas it's supposed to be 25-45 deg.
Also, the bolt indicated is actually right up against the Tie Bar mounting on the underside, preventing moving it rearward just an inch or two...

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When I actually got the Servo off, it was evident why it had been mounted upside down. The 2 mounting bolts are not on the centre line, they are about 1/3rd up. No way it's just a flip 180 deg.

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The instruction booklet comment "Position of 'L' shaped mounting bracket may need to be modified to suit installation" was now more relevant....
So Step One, bend the bracket to a more suitable angle.

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Step Two, in my case I used a short length cut from some 'Dexion' type shelving upright. Bolted into the Mounting Plate, it allowed me to mount the Servo such that the Air Control Valve is at the 5 O'clock position (viewed from the business end). I used a low profiled domed head bolt to attach the additional plate, which had the added advantage or angling the Servo a few degrees to one side relative to the mounting plate. This gave some additional clearance for the hose fitting connecting to the Air Control Valve, which had been a bit close to the Engine Mounting.

On assembling it all together, I place a thin rubber washer between the Dome Head and the Servo body just to prevent any possibility of the bolt rubbing on the body. You can just see it in the 4th image.

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You'll note I also slackened off the clamp around the rim, in order to rotate it and stop the actual clamping bolt fouling . Duly re-tightened of course.

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[geoberni]

Part Two, fitting it all back in ....(there's a max of 5 images per post)
So the original installation had used the 'P' Shaped Steady Bracket mounted down to the engine bay floor.
That was now well short, due to having fitted it at the correct angle.
This also meant the connection from the 3 Way to the Servo Out connection was now considerably shorter than required.

So, cut the Support to length and mount on the inner wing. Make up a new length of brake line, luckily I had some left from a job on another car a few years ago (never throw away potentially useful stuff )

I ran all 3 pipes near each other and covered them with appropriate size plastic sleeve, before taping them together for mutual support.

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Seen through the hole at the back of the engine bay

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I roughly bled this work by cracking open the line at the 3 way, just to prime the Servo.

Proper bleeding will get done in the next week or so after the wheel cylinders have been replaced.

Lessons learnt?
If you have a Servo mounted upside down and want to correct it make sure you understand the way it is attached to the Mounting Plate. Check what angle it's been mounted at, the job may be a bit bigger than it first looks.

[Flywheel]

Hi Geoberni, thanks for sharing your photos. I'll sort my own servo out very soon.

Much to my surprise, I had no idea that these servos should be installed this way around. No wonder the brake pedal on my traveller has a soft pedal.

Please keep us posted on your job. It's interesting to see how others problem solve.
Thanks again. Jonnie.

[Boomlander]

Hi all,
Just been reading this very informative post regarding brake servo positions.
I was under Willum's bonnet this morning and, lo and behold, my brake servo also seems to be positioned incorrectly!
This was installed by "professional" engineers with an invoice detailing the work carried out and parts used.
What effect does the position have on braking performance as I expected a much sharper response from the front disc brakes. Sorry for my ignorance but I have to admit I'm not familiar with the set up of servo systems and any help would be much appreciated.

[geoberni]

Well if you've read all the above, you will see from my post dated 30th April that the installation booklet says the Air Control Valve should be at least 30 deg below horizontal to help with bleeding.
Basically if it's on top, there's air trapped in there.
Air equals spongy brakes....

See this Video (Although the guy does get it wrong when he speaks of Air Valve vertical +/- 30 deg, it is actually 30 deg or more below Horizontal).
https://www.youtube.com/watch?v=7-xPLRbDiDw&t=434s

[jagnut66]

Basil's brakes are really seized up

Hi Berni,
One point I forgot to mention before when I first read this post, which you may or may not be aware of, is that the new replacement drums available these days have a reputation for going oval.
So if you have a pair of good original drums (for either the front or rear) they are worth hanging onto.
If you haven't got it all back together yet, they might be worth checking.
Best wishes,
Mike.

[kevin s]

The one I fitted to ours didn't specify which way up the atmospheric air inlet valve goes but was very specific that the hydraulic outlet must point up ( I think it was around 30 degrees). It bleeds easily like this.

This is basically what I have, interestingly it is mounted with the air valve on the top. So it seems for some the valve on top is OK.

https://www.carbuilder.com/uk/remote-brake-servo