More brake cable questions
Moderators: Ian Grace, Will Grace
More brake cable questions
More brake cable questions I'm afraid. Can anyone tell me how is the measurement of 42.5 inches for the (later) front brake cables is determined. By my measurements of the existing cables it does not seem to be the distance from the brake shoe camshaft lever to the lever on the countershaft. The cables on my SV are dangerously long at 46" and 47.5" as the 4 inches of threaded rod at the countershaft is fully taken up. Clearly they need to be shorter. Is the 42.5 inches the overall dimension from camshaft lever to the end of the threaded rod?
Re: More brake cable questions
Richard,
I'm in Idaho for the weekend, so cannot check, but I'm sure that the dimensions quoted for cable lengths are from the clevis pin hole one end to the extreme end of the threaded rod the other end.
Ian
I'm in Idaho for the weekend, so cannot check, but I'm sure that the dimensions quoted for cable lengths are from the clevis pin hole one end to the extreme end of the threaded rod the other end.
Ian
Re: More brake cable questions
Thanks Ian. I've measured again and think that the measurement must refer to the overall length. My cables are only ten or so years old but when I had them made I had no information about proper length and made a guess based on the old cables then on the car. I will eventually get myself a new pair but for now will have them shortened and give myself some long overdue adjustment to the front brakes.
Re: More brake cable questions
I've had the front cables brought to 42.5" and now they don't fit at all...too short by about half an inch to even meet the countershaft lever pin. The brake camshaft levers lie forward at about 60 degrees as recommended and I've slackened off the countershaft completely so that is not the problem. I'm not sure how much threaded rod should project through with the brakes off but clearly without any there is something wrong. Could it be that the cable is not flexible enough to wrap snugly around the pulleys and I am losing length as it bows out between the pulleys? It doesn't seem likely but the rear brake cables measure less than specified at 47" and in a straight run meet the levers with plenty of rod projecting.
Hmmm, perhaps I should sleep on it and try again in the morning.
Hmmm, perhaps I should sleep on it and try again in the morning.
Re: More brake cable questions
Richard,
Could it be that the chsssis pulley brackets are wrongly positioned on the chassis, thus lengthening the cable run? Any chance of some photos?
The front cables should be made of wire rope, not regular cable like the rerar cables. Wire rope is thinner and more flexible and should wrap around the pulleys easily.
Here's the relevant Brivec catalogue page, giving all of the cables and "overall" lengths:
Could it be that the chsssis pulley brackets are wrongly positioned on the chassis, thus lengthening the cable run? Any chance of some photos?
The front cables should be made of wire rope, not regular cable like the rerar cables. Wire rope is thinner and more flexible and should wrap around the pulleys easily.
Here's the relevant Brivec catalogue page, giving all of the cables and "overall" lengths:
Re: More brake cable questions
Ian,
It occurred to me while I slept that I should have used a piece of string to determine precisely the distance from the clevis pin hole in the front brake cam lever, round the two pulleys and back to the cross bar clevis pin before cutting the cable. We are away on Stradbroke Island for a week or ten days but I will certainly carry out this task when I return and before making any further decisions. At that time I will photograph the pulleys and their mounts for you but I am pretty sure that this isn't the problem. The idea that the front and rear cables are of different construction is new to me but of course absolutely sensible. Can you let me have some indication of the diameter and composition of each that you have found successful?
Do you know if the S & VM cables make this distinction of construction and therefore flexibility? I assume that the fittings on the MMM set are in BSF and it is probably simpler to buy from Mike Dowley than continue to experiment and find someone here who can do the work satisfactorily. While I would like to use my original cable end fittings this may not be possible and turning a BSF thread to new fittings will be another task perhaps best avoided.
Thanks for your help as always.
It occurred to me while I slept that I should have used a piece of string to determine precisely the distance from the clevis pin hole in the front brake cam lever, round the two pulleys and back to the cross bar clevis pin before cutting the cable. We are away on Stradbroke Island for a week or ten days but I will certainly carry out this task when I return and before making any further decisions. At that time I will photograph the pulleys and their mounts for you but I am pretty sure that this isn't the problem. The idea that the front and rear cables are of different construction is new to me but of course absolutely sensible. Can you let me have some indication of the diameter and composition of each that you have found successful?
Do you know if the S & VM cables make this distinction of construction and therefore flexibility? I assume that the fittings on the MMM set are in BSF and it is probably simpler to buy from Mike Dowley than continue to experiment and find someone here who can do the work satisfactorily. While I would like to use my original cable end fittings this may not be possible and turning a BSF thread to new fittings will be another task perhaps best avoided.
Thanks for your help as always.
Re: More brake cable questions
I cut it twice - and its STILL too short! The old ones are the best!
The MMM cables are Bowden type and so don't need to be made of wire rope, as they don't use pulleys. You cannot use M type cables on Minors because the brake cross-shaft was positioned differently on the M, so the cable lengths don't work for the Minor.
I suggest you make contact with Ian Harris in the UK who I believe has new Minor cables (of the correct length!), but would in any case be able to advise on cable spec. if you want to make your own up. Ian can be contacted at ian@harris84.fsnet.co.uk.
Ian
The MMM cables are Bowden type and so don't need to be made of wire rope, as they don't use pulleys. You cannot use M type cables on Minors because the brake cross-shaft was positioned differently on the M, so the cable lengths don't work for the Minor.
I suggest you make contact with Ian Harris in the UK who I believe has new Minor cables (of the correct length!), but would in any case be able to advise on cable spec. if you want to make your own up. Ian can be contacted at ian@harris84.fsnet.co.uk.
Ian
Re: More brake cable questions
Thanks Ian,
I certainly don't want Bowden type cables although I'm sure they would work more consistently and with less roadside fettling required.
I will contact Ian Harris next week and in the meantime push ahead with my string theory* of brake cable fitting.
* for the scientifically minded
I certainly don't want Bowden type cables although I'm sure they would work more consistently and with less roadside fettling required.
I will contact Ian Harris next week and in the meantime push ahead with my string theory* of brake cable fitting.
* for the scientifically minded
Re: More brake cable questions
That would be the 20 dimensional braking system?!
Re: More brake cable questions
I've contacted Ian Harris and he has given me useful advice about cable diameters...3mm or 4mm from his supplier. My cables measure 3.8mm but are of a composition that doesn't allow them to turn around the pulleys without bowing out and hence shortening the available length. My cable length measurement (how long is that piece of string?) comes in at close to 42" with brake cam lever and cross shaft at maximum off position. Too close for my inflexible cables.
It seems that a new set from Ian are in order. I'll write to him tonight.
It seems that a new set from Ian are in order. I'll write to him tonight.
Re: More brake cable questions
Ian,
This afternoon I remembered that on October 31 you asked "Could it be that the chassis pulley brackets are wrongly positioned on the chassis....?" I replied was that I didn't think that this was the problem. I have now noticed that the early SV lubrication chart clearly shows the front brake cable passing through the chassis pulley at something well beyond the 90 degrees that the cable turns through on my car.
I've just been to look and there does seem to be another mounting position further aft. I'll have a better look tomorrow morning but even looking at the photograph I posted this morning it seems that my chassis bracket might, as you anticipated, be too far forward "thus lengthening the cable run".
...and I've just ordered the new cables from Ian Harris.
This afternoon I remembered that on October 31 you asked "Could it be that the chassis pulley brackets are wrongly positioned on the chassis....?" I replied was that I didn't think that this was the problem. I have now noticed that the early SV lubrication chart clearly shows the front brake cable passing through the chassis pulley at something well beyond the 90 degrees that the cable turns through on my car.
I've just been to look and there does seem to be another mounting position further aft. I'll have a better look tomorrow morning but even looking at the photograph I posted this morning it seems that my chassis bracket might, as you anticipated, be too far forward "thus lengthening the cable run".
...and I've just ordered the new cables from Ian Harris.
Re: More brake cable questions
Richard,
Here's a very similar perspective, showing the brackets mounted just behind the front wing support. I will check my McEvoy chassis tonight and come back to you.
Here's a very similar perspective, showing the brackets mounted just behind the front wing support. I will check my McEvoy chassis tonight and come back to you.
Re: More brake cable questions
Ian,
Thank you for the drawing. I've been reading a forum post on this subject from early December 2010 (JF 4238 Minor Saloon). You comment on December 5 in that series that "..it certainly looks like the chassis bracket on the SV car is mounted further forward than on the OHC car". You don't identify the source of the photograph illustrating this or the date of the car but it does raise some more doubt in my mind.
I'll be glad to have your observation of where the brackets are on the McEvoy. There are so few Register cars here to check these things. My strategy this morning is to wait for the new cables from Ian Harris and then, if they still seem too short, look at moving the chassis brackets.
Thank you for the drawing. I've been reading a forum post on this subject from early December 2010 (JF 4238 Minor Saloon). You comment on December 5 in that series that "..it certainly looks like the chassis bracket on the SV car is mounted further forward than on the OHC car". You don't identify the source of the photograph illustrating this or the date of the car but it does raise some more doubt in my mind.
I'll be glad to have your observation of where the brackets are on the McEvoy. There are so few Register cars here to check these things. My strategy this morning is to wait for the new cables from Ian Harris and then, if they still seem too short, look at moving the chassis brackets.
Re: More brake cable questions
Richard,
A couple more images.
This one I just took with my cellphone out in the garage. It's the McEvoy chassis and I loosely hung the brake pulley bracket on the chassis. The photo was taken directly above the pulley. It looks like the pulley centre should be virtually perfectly in line with the aft edge of the front chassis cross-member.
(Note that the 1933 pulley bracket is a little broader/stronger than your earlier version, but the position of the pulley wheel should be the same.)
And here's another view of the general arrangement:
A couple more images.
This one I just took with my cellphone out in the garage. It's the McEvoy chassis and I loosely hung the brake pulley bracket on the chassis. The photo was taken directly above the pulley. It looks like the pulley centre should be virtually perfectly in line with the aft edge of the front chassis cross-member.
(Note that the 1933 pulley bracket is a little broader/stronger than your earlier version, but the position of the pulley wheel should be the same.)
And here's another view of the general arrangement:
Re: More brake cable questions
Ian,
Just so, and just where the brackets are on SV8159. Thank you.
The pulley position might well have been the problem. My doubt was reinforced in large part from my reading of the 1931 SV Minor Lubrication chart (below) which seems to show the chassis pulley well back from the cross member and the resultant cable angle well beyond the existing.
http://www.vintageminor.co.uk/secure2/L ... 0chart.JPG
Just so, and just where the brackets are on SV8159. Thank you.
The pulley position might well have been the problem. My doubt was reinforced in large part from my reading of the 1931 SV Minor Lubrication chart (below) which seems to show the chassis pulley well back from the cross member and the resultant cable angle well beyond the existing.
http://www.vintageminor.co.uk/secure2/L ... 0chart.JPG
