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MG MGB Technical - Parking Brake Cable

I have both the wire wheel and rostle wheel axle parking brake cables and have measured them to ensure I put the wire wheel parking brake cable on my 68 MGB. After I installed the cable, I fully tightened it at the brake handle and it still does not put enough tension on the brakes to hold the rear wheels firm. I also just finished rebuilding the entire brake system with new shoes, pads, rear cylinders, front calipers , hoses and master cylinder. The hydrolics work great and all 4 wheels brake firmly when I push the pedal The rear wheels turn with a slight drag without the brake pedal pushed or parking brake engaged. Did I misroute the cable? I followed the pictures in the Haynes book and Porter's book. Or did I miss something else?
Cris DeYoung

Hi Chris
This might not be much help but I had this problem many years ago, and after much head scratching and several cups of tea eventually figured out that the Haynes manual was wrong, only trouble is its so long ago I can't remember the details but they showed the parts in the brake drum assembled wrongly. Maybe someone who has done this recently could be of more help.
Ron
r algie

Have you got the wheel levers the right way around?. Its been a while but I seem to recall that its possible to get these wrong and about 1 cm of slack results.
Peter

Know what you've got. The adjustment nut is all the way home and still, brakes aren't tight.

I'm lead to believe that somehow, some cables were made a bit longer, or some other technical screw up.

Some time in the future, I'd like to place a spacing tube, or move the cable fixing block back an inch or two -- something to shorten up the cable lenght.

That's not much help or solution, but you are not alone with this problem. That's the best "help" i can give.
glg

I can only commisserate. Same problem. Too much slack in the hand brake cable, no matter what I do.
Kim de B

I recently installed a brand new brake cable and still had excessive slack. I was too embarrassed to admit that I couldn't thnk through the problem. Now, emboldened by the knowledge that I am not alone and that others have had the same results, I conclude that there is some easily overlooked step or, perhaps more likely, the blasted cables are too freek'n long. I have looked at ways of shortening the cable, but with the extreme pressures encountered under use and the critical nature of the assembly, I have not settled on anything acceptable....yet.
Dean
Dean Lake

Cris,
I just replaced the parking brake cable (and adjusted the brakes) on my '69 MGB-GT yesterday. I was disappointed when I finished because I had to tighten the nut all the way home for them to hold. That's where it was before I replaced it. Very frustrating!
Paul
Paul S. Canup

It may truely be that the cable is to long, try every way you can to be sure that it's installed correctly if that fails stack washers on the adjustment end of the cable until you can tighten the cable enough to make it work right, measure the stack of washers this is the amout of cable you have to cut off the non threaded end befoe you braze a new cable end on. I've found that the cables from otherwize good suppliers can be pefect or long [I never got a short one] depending on the phase of the moon or some other power unknown to mere mortals.I've also never had a problem with a cable I've shortened, but do so at your own risk as the strength of the cable is directly related to the skill of the tecnician- RIC
Ric

After the comment from R Algie, I looked at the Haynes and the Bently manuals as well as Porter's book . On page 253 of the Bently manuel it shows what appears to be the right side wheel and on page 254 it shows the left side wheel assembled. Then I went to Haynes on page 152 and Porter's book pn page 201. All of them appear to show the same pictures. I then went and pulled the drums off the wheels and looked to check the cable levers as suggested by Peter from OZ. All appears to be correct.. Could the brake shoes be wrong? Will the little slot for the cable lever fit over the trailing edge of the cable lever? Would this tighten up the cable. The other thing I was thinking about is increasing the amount of cable between the two holding brackets, the one that attaches to the battery box and the one that attaches to the axle. As these are fixed i position, would additional cable between them help take up the slack? I'll have to give that a try next. Thanks for all the help and commisseration. I've had this car up on jack stands for over 18 months and I'm finally getting close to getting it on the road again. I can almost taste it. This little setback is not so disturbing now.
Cris DeYoung

Been thinking about this all day --- let me rephrase that --- it's been eating at me -- -

I can get by with the way it is, but then too, it just becomes one of those little pain in the neck that is more bothersome.

I've decided to move the cable fixing bracket -- the one held to the transmission tunnel with an inside nut -- back about three inches.

The thought of replacing this realitivley new cable on the chance of getting the correct lenght, and going through all that underneath work installing it seems too costly in time and money.

The procedure would be measure lenght of threaded portion of the cable and any other slack, undo the fixing bracket, drill a new hole towards the rear, close the old one and re-install.

Sounds like it'd be easy and fun -- as i sit here at the keyboard. Whatta ya think?
glg

It can only be cable length if you can't lift the lever far enough to put the brakes on. If you lift the lever and it gets tight after 4 to 6 clicks but still doesn't stop the wheels something else is wrong. But this is only a parking brake and not an emergency brake, it doesn't offer much by way of retardation when moving. You can get the shoes in wrong, each shoe has the friction material offset to one end of the plate, all four shoes should be fitted so that when moving forward a point on the drum passes over the bare part before it reaches the friction material. The shoe levers have grooves the shoes ride in and these can wear, reducing the efficiency of the handbrake but not the footbrake. When the handbrake is on the lever that sticks out the back of the backplate should be at right-angles to the backplate, and the part of the lever the cable attaches to should be parallel to it. If the cable part has been pulled further away from the backplate than that the grooves are too deep, they can be filled with weld and filed to suit. If the handbrake lever *does* rise too far, and I have just had to do this on one of my cars, fit a spacer on the compensator (on the dif casing) end of the short cable. My lever was moving about 7 clicks with all the adjustment thread taken up, I now get 4 clicks with about 1/3rd of the thread. If you move the handbrake end there may be reinforcing on the tunnel that you are no longer using and the tunnel metal will twist, turning the cable through a sharp angle and causing it to rub on the bit on the end of the sheath making it stiff and wear quickly, the other of my cars was doing that even though it was in the right place, I had to add more reinforcing.
Paul Hunt

Thanks Paul -- there was some confusion in replacing the brake shoes regarding that off-set. (just completed a shoe-spring re-fitting. I'd expect a failure on my part in comprehending the finer points.)

I'm confident in cable installation and hand brake lever. From the get-go -- (that's from the very begining) the parking brake adjustment (at the base of the hand lever) has always been screwed tight.

Shoe adjustment is reasonably correct and brake pedal is high -- aprox two inches to full on. With pulling on the hand brake, it's all the way up but not tight.

Have you heard of "long cables" being sold as replacements?

glg

Are these problems on wire wheel cars only? I ask because within the last two years I have replaced the handbrake cable on both my cars and had no problems. My handbrake will hold the car on a hill with no problem. Both cars have steel wheel hubs and axles.
I got my cables from Gordon at The B Hive.
http://www.thebhive.com/index.html
Clifton
Clifton Gordon

Hi Cris,
I had the same problem a few weeks ago. I took my '70 MGB to my mechanic, told him I had replaced the cable approx. 2 months previously, and was not happy having to pull the brake lever up as far as it will go before it holds, even though the adjustment was at its end.
He told me straight off that it was probably the small lever under the car where the end of the brake cable attaches to the base of the hand brake lever. The lever did not look bent or misshapen. However, it apparently was bent.
This did not allow any further adjustment. He heated the lever up, bent it forward, (ie. towards the front of the car), and it now works wonderfully, and I still have some adjustment left.
Try this it may be your problem.
All the best & good luck.
CARLO

Carlo thanks for the information. I'll give that a try. Today I added spacers on the compensator as Paul suggested. It helped a little. Then I took out the little spring that is on the cable where it attaches to the brake handle under the cockpit and tightened the nut all the way down. The brake handle still goes up 7 clicks, but it now holds the wheels tight. I hope this is OK. The other option I'm looking at is having the cables sortened on the (New) cable. Thanks again for all of your help.
Cris DeYoung

A steel wheel handbrake cable will be too long on a car with a wire-wheel axle (and vice-versa too short). 7 clicks would be a testing station failure here.
Paul Hunt

Any thought on just moving the stop at
the hand lever toward the rear?

One could just drill a new hole in the tunnel
to affix the cable stop farther back by an
inch or so. Still be able to actually
use the cable adjuster.

'Thought that the handbreak was a one piece
unit. I can see it gettin' bent up though.

HowY

FWIW I have replaced both cables on my two B's in the last few months. One has steel and the other wire wheels and in both cases the cables were correct in part number but long when fitted. I went for the option of drilling a new hole. It worked a treat except that the distance it needed to be from the original was half what I had estimated. Never quite understood why this was so, as I was convinced at the time that I'd got the initial measurements right.

Steve Postins

Steve, can you give a little more detail on how you calculated how far back to drill the new hole? It looks like the best fix
Cris DeYoung

HowY, see previous postings in this thread.
Paul Hunt

Oh...

Sorry, see that this was mentioned...

I got lost in the seven clicks thing...

Forgive me wastin' 14k of bandwidth
HowY

Cris,

As far as I recollect I had the threaded end of the cable screwed through the adjusting nut as far as it would go, compressing the spring right down, but the shoes were only just starting to touch the drum. I remember thinking that there was about 3" of thread sticking through the nut, so if I drilled a hole about 2.5" back that would give a tight brake and plenty of future movement if the cable stretched. In fact the hole only needed to move about 1.25". Either something doubles the effect or my estimations were shoddy. Probably the latter.
Steve Postins

I had the same problem when fitting a new replacement cable. After a time, the cable stretched out even more. Like someone mentions above, I solved it by building a standoff spacer, similar to an adjuster on a bicycle hand brake lever. I made mine out of two pieces of tubing, welded together. Smaller diameter (0.375" OD) slides into the larger (0.625" OD), to give the necessary step changes. When done I cut a slot, on the side, to allow it to slip over the cable. The length of the smaller tube was 1.25", although 1.5"-1.75" would have been better. Now I have most of the full range of adjustment.
Terrence Goodell

A hate bodging, but unlike drilling another hole in the tunnel at least the cable bodge is removed (eventually) with the old cable.
Paul Hunt

Paul, translation please into English -

((the US variant))

Bodging and bodge --

What's them mean?
glg

Professionals do the job properly. The other way is to bodge it, in which case you become a bodger. Of course there are also professional bodges and likewise professional bodgers (always PO's and never the current custodian).

I'll be giving Paul's method a go on my GT as a CC I reckon it falls into the realms of "custom engineering".
Steve Postins

This thread was discussed between 25/05/2003 and 30/05/2003

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