mysterious brake problem

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DENNIS NICHOLAS
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mysterious brake problem

Post by DENNIS NICHOLAS »

I have an Austin 7 fitted with a hydraulic brake conversion that uses Morris Minor back plates. The only modification is that the centre is cut out and a recessed section welded on to set the plate nearer to the centre of the car so that the shoes are in line with the drum, otherwise all the bits are standard Morris Minor 7 inch brakes.

THE PROBLEM
Even with new linings the adjusters have to be turned several notches to get the linings next to the drums. This means one runs out of adjustment so can never use the full lining thickness.
So far I have used spacers around 1.8mm to 3.2mm put in the rear pivot block slots and one on end of cylinder slot on the rear and on the fronts a spacer on each cylinder slot.
I can't imagine this is normal!! with all the Mo. Mins. running around with spacers (I don't remember such problems when I owned Minor 1000 Estates.
As far as I can see the problem can only be caused by:-
1.The pivot block being too short......mine is 36.7mm(ish) (remember it is a standard back plate untouched at this part)
2. The cylinders being too short.....mine are 55.12mm. (I know there are 7/8" and 3/4" versions....I have measured both and both that I have are same.
3. Shoes ....non notched - stand web on flat surface and height of my lining in middle is 62.4mm (2.4") with about 4mm thick lining left. Notched shoe same.
Could the shoes be too short?? i.e. the curved bits at each end should be longer?
4. adjusters -2 small on front and one larger on rear have distance of - REAR 10.44mm between bottom of flat of mask and top of spindle that shoe slot rests on. This distance increases from 10.43 up to 20.08mm at notch16.

My linings are 6.75 by 1.22.[frame]Image[/frame]
panky
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Re: mysterious brake problem

Post by panky »

Could it be possible that the drums have been skimmed at some time in their life?
Image
bmcecosse
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Re: mysterious brake problem

Post by bmcecosse »

I have used 'shims'under the rear edge of the shoes - works well, and keeps the shoe more 'square'to the drum. The later 8" brake adjusters are bigger - you could use them.Are you sure the adjusters are running out of clicks - or are they just wedging against the shoes before reaching full adjustment - check with the drums off. The only sensible answer here really is that the drums are worn/have been skimmed. Do they accurately measure 7" int diameter?|
ImageImage
Image
DENNIS NICHOLAS
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Re: mysterious brake problem

Post by DENNIS NICHOLAS »

I am still desperately looking for an answer to this problem!
I need people to send in the measurement of the distance between the bottom of the pivot block slots where the shoes ends sit and pivot/slide .....Year - distance. (see left hand block in the photo of my original post)
Also distance between bottom of cylinder slot and face of cylinder piston where adjuster mask sits. Year - distance - state 7/8 or 3/4 inch bore.
Also same for front cylinders.

Bewildering choice of shoes out there to buy.....which are recognised as the best?....original Lockheed or Mintex or or QH or are pattern shoes just as good.
I have some brand new 7 inch drumms. (a part worn one measures + 15 thou of ware using an internal micrometer (ie 7.015 inches). 8 notches of adjustment to get old shoes with 4mm lining in middle to touch new drums!!)

Dennnis
RobThomas
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Re: mysterious brake problem

Post by RobThomas »

Should have the dimensions for you tonight, Dennis. Car is wedged in the workshop and I can't get to it without moving some stuff out of the way.

[frame]Image[/frame]
Cardiff, UK
RobThomas
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Re: mysterious brake problem

Post by RobThomas »

1.450 for the welded metal plate. 2.170 for the 2 surfaces the shoes rest upon at the cylinder end. How do those compare? I shoved one of the kids down the gap (they are more flexible than me and fit into tiny spaces) and got them to measure it. Not sure how well calibrated a 10 year old kid is or how good he is at reading dials.

I can get a more accurate figure if you need it.
Cardiff, UK
RobThomas
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Re: mysterious brake problem

Post by RobThomas »

Got him back in there to take a photo of the dial calipers in position. 1.440 and 2.150 inches (+ or - a few thou)

He doesn't like spiders so is not well pleased at the moment! :D
Cardiff, UK
DENNIS NICHOLAS
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Re: mysterious brake problem

Post by DENNIS NICHOLAS »

Rob thank you.
Those measurements coincide with mine.1.45 and 2.17. So really that just leaves the shoe lengths. I have some new Quinten Hazel ones coming next week so will have to compare them with my old ones. Who knows maybe the old shoes I have which look the same were from a slightly different 7" Lockheed setup for example one with a 2 piston cylinder which maybe used a slightly shorter shoe.

Nice little special.
Sorry attached photo of my Sp is so small but it is the only one I have on this computer.
The Nippy was a written off crashed wreck without engine which I straitened out and got back into use again using a BMC A 948 engine which broke a piston and precipitated major rebuild of whole car and acquisition of a 1275 A+ mating to a 5 speed Toyota box hence quest for really good brakes! . It looks standard except for the 15" daily use wheels ( I used to use its 19" wheels for the MCC trials).
Dennis PS Kid/spiders.....has he tried them lightly grilled with a little black pepper washed down with Devon zyder.....wonderful...not so sure about the spiders though.[frame]Image[/frame]
DAVIDMCCULLOUGH
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Re: mysterious brake problem

Post by DAVIDMCCULLOUGH »

I would recommend the Mintex as being the best option of shoe, gives a good bite and is so much better than the cheaper unbranded shoe.


Too many Minors so little time.....
oliver90owner
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Re: mysterious brake problem

Post by oliver90owner »

Dennis,

I would take that recommendation of Mintex over Quinton Hazell with a pinch of salt. Mintex may be better (I don't know), but QH, as a well branded supplier of automotive parts to the motor trade, for many years, likely has the grade and quality you need. Definitely branded, so not necessarily a cheaper, nor unbranded product. I've not looked at comparative prices nor do I have any connection with QH, other than using them for a whole variety of automotive products over the last 40 years or more.

RAB
RobThomas
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Re: mysterious brake problem

Post by RobThomas »

Mind you, if you don't have the late Ruby torsion arms and Bowdenex cables then great brakes will start bending everything. :D :D :D

If you ever get the chance to send me some photos of the engineering of your car then I'd be very grateful.

Cheers

Rob
hfh200 at hotmail.co.uk
Cardiff, UK
liammonty
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Re: mysterious brake problem

Post by liammonty »

oliver90owner wrote:Dennis,

I would take that recommendation of Mintex over Quinton Hazell with a pinch of salt. Mintex may be better (I don't know), but QH, as a well branded supplier of automotive parts to the motor trade, for many years, likely has the grade and quality you need. Definitely branded, so not necessarily a cheaper, nor unbranded product. I've not looked at comparative prices nor do I have any connection with QH, other than using them for a whole variety of automotive products over the last 40 years or more.

RAB
RAB - be aware that QH was recent'y taken over (I think in 2013, after their parent company went into administration), and that quality of their parts post-takeover is far from what it used to be. I have personally experienced failure of several QH parts fitted since then. Unfortunately, the QH parts you fitted 40 years ago are not the same quality of QH parts available to you today.

Regarding brake shoes, the Mintex ones currently available for the Minor 7" drums are very good (again from personal experience). I suspect if you could get hold of some NOS QH ones they would be great too, but I'm not certain of the quality of the new ones. They are likely to still be better than the totally unbranded ones on offer these days at least.
amgrave
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Re: mysterious brake problem

Post by amgrave »

I'll throw my hat in the ring for Mintex too. I fitted them all round a couple of years ago and noticed the difference straight away and not had any problems with them since. I too have used QH parts in the past but not sure if the quality is up to their usual standard these days, they probably out source for their parts and come up against the same problem as us that ol "tin huts in far away places" thing.

oliver90owner
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Re: mysterious brake problem

Post by oliver90owner »

Liammonty

Thanks for the heads upon yet another change of ownership, but the point, really, was that QH are not an unbranded item. As such, they are accountable and not like these 'unbranded' boxes with no name and probably no place of origin. Do Mintex actually manufacture all their products, or do they import under a strict quality testing regime?

I once worked at a place where all the electronics, for the items manufactured, were made in China, but QC was so stringent that every batch used was previously ruthlessly checked, with anything below spec rejected. It worked. They were proud to put their name on a quality product and stand by the reliability of an item in a competitive market.

RAB
amgrave
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Re: mysterious brake problem

Post by amgrave »

No idea where Mntex get their shoes from or who makes them and don't really care but I do believe in word of mouth and I have heard nothing but good for Mintex. I tend to go by recommendation most of the time these days as you never know what you are buying any more.

whyperion
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Re: mysterious brake problem

Post by whyperion »

Do you have the correct size adjusters fitted - I understand the snails came in two sizes?
DAVIDMCCULLOUGH
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Re: mysterious brake problem

Post by DAVIDMCCULLOUGH »

oliver90owner wrote:Dennis,

I would take that recommendation of Mintex over Quinton Hazell with a pinch of salt. Mintex may be better (I don't know), but QH, as a well branded supplier of automotive parts to the motor trade, for many years, likely has the grade and quality you need. Definitely branded, so not necessarily a cheaper, nor unbranded product. I've not looked at comparative prices nor do I have any connection with QH, other than using them for a whole variety of automotive products over the last 40 years or more.

RAB

Rab,

I wasnt referring to QH as unbranded, I was referring to the £11.50 shoes that come shrink wrapped with no label on them and offer very little in the way of braking and just seem to shine the linings up with use! Having fitted Mintex to several cars over the last couple of years I can assure you that they offer a much superior brake and are well worth the extra few quid. I cant say about how long they last as yet though. Personally I still look out for old stock shoes for my own cars which arent that hard to find at autojumbles.


Too many Minors so little time.....
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