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MG Midget and Sprite Technical - Hand brake compensator

Ref pn ATA7320. Could anyone out there please let me know the thread size for this part? Many thanks, as ever. Dave
David Cox

If my memory serves me correctly, from whence I last restored one, it is a Whitworth thread.
Alan
Alan Anstead

It certainly looks like a Whitworth.

I think I have one on the bench - I will see if I can measure it.
Dave O'Neill 2

thanks..yes ..it is a coarse thread but any more detail would be welcomed. Dave
David Cox

..just another question...when the handbrake is actuated by the cable...does the compensator turret turn on the horizontal thread? there is no lubrication provision if that is the case?...anyone??
David Cox

It shouls not turn on the horizontal thread. Mine has a lock nut to hold the compensator in the vertical position.
Bob Beaumont

The thread is 3/8” BSW.

That’s interesting Bob mine doesn’t have a lock nut and not shown in the parts list - I have a couple of spares without as well, but they do wear on that thread I’ve found and I was thinking about welding in a new threaded portion.


richard b

thanks for input, chaps...most appreciated. The one on mine is clearly worn and it's a job for Saturday. Dave
David Cox

Mine is a'1/2' nut and its been on there for the last 40 odd years of my ownership! A PO mod perhaps
Bob Beaumont

Never seen a locknut on one. It needs a certain amount of movement to function properly.
Dave O'Neill 2

No lock nut on mine either, and the thread is worn, so it must move a fair bit. I grease it regularly too.

Perhaps no lock nut was designed in, as lateral movement was thought to be needed. But as Bob has shown, a lock nut does no harm, and the hand brake still works, nut or no nut.
anamnesis

all interesting stuff, thanks

subsidiary question: the hand brake rods are different for wire wheels and disc wheels....does anyone out there have the lengths for these different pairs, pleas? many thanks...Dave
David Cox

David
My rods, on my Sebring Rep, are adjustable now that I have modified them.

Anam
The actuator must move about quite a bit as the thread, of the bracket extension, wears a lot over the years. The grease only protects the upper part of the actuator - the part that the handbrake rods attach to.
It might be possible to drill a grease conduit in the threaded bracket extension and fit a grease nipple so that the thread gets some lubrication.

Alan Anstead

interesting mod, Alan. The horizontal thread on mine has worn considerably, despite lubrication..but I guess as it's 55 years' old now it doesn't owe me anything! That it HAS worn would confirm that some degree of rotation must occur as the handbrake is applied. The NOS replacement parts are obviously a snug fit on the threads, and I too had thought about drilling and tapping a greaser into the square headed carrier.
David Cox

Maybe wear has been induced by vibration of the rods while on the move?

The clevis end of the adjustable ones from Moss (adjustable so they only have to stock one item for steel and wire wheels) are the same as the clevis on the brake pedals (apart from the thread. see next sentence).
I wanted a clevis for a modified pushrod so bought one from Moss but the thread of the clevis was different to the thread on the original modified pushrod!!!!!!!
Rob
MG Moneypit

Something like this Alan ?

A boss or nut silver soldered or welded on would give a bit more ‘meat’ for tapping as this is bottomed to give a base for the spring - I drilled the grease hole 0.7mm.

R.

richard b

I am not convinced by the earlier comment (Bob) that the"tree" part shouldn't turn on the BSW threaded piece. When the handbrake is applied there should be a some movement available to balance the pull on the rods to either brake to automatically apply the same force. I agree that the tree part needs to be held close to vertical, but a few degrees of rotation about the threaded part will provide the equalisation needed.
GuyW

some wise heads from the motor trade who cut their teeth on these cars would confirm that some movement on the horizontal is needed. What Guy says.
David Cox

I won't comment further other than mine works fine and
locks the rear wheels very efficiently. I just offered my comment based on my personal experience but I am certainly not going to get into an argument about it!!


Bob Beaumont

Sorry Bob, it wasn't meant to be an argument as such, just a slightly diferent view. No doubt if your brake shoes are accurately adjusted then the pull needed to each side will be the same anyway and will lock both wheels as yours do. Enough said on the matter!
GuyW

If you're going to go round upsetting everyone Guy






. . . there'll be nothing left for me to do. 🤣
Nigel Atkins

David,

w/wheel axle steel wheelaxle
L R L R
rods 360 660 375 670 mm
14-3/16 26 14-3/4 26-3/8 inch

rod lengths are measured between hole centres of the yokes
how DO you format a table on this BBS? Been over 20 years andnever can do it!
David Smith

Put it in a picture :)
anamnesis

Richard B
Took your suggestion (Top tip) and welded a 1/4unf nut to the base of the square to give the thread, for the nipple, some depth.
Prior to welding I drilled the grease conduit hole with a centre drill, on the lathe, so that it had a nice chamfer.
Alan

Alan Anstead

thanks for the measurements, David.
and you've started something here, Richard B..I too have welded a greaser onto the carrier ...why did MG not do this in the first place? Did they assume, with an exposed thread end, that a dab of grease would be pressed in by hand when the rest of the car was lubricated?? Dave
David Cox

Another 'Thank You' to Richard B for the Top Tip. My brake compensator 'carrier' now has a welded on nut and grease nipple. All part of my quest for an effective hand brake.

Incidentally, the thread for the carrier on the handbrake bracket has a distinct bend, fortunately not enough to prevent the carrier from travelling the full length of the thread. I considered trying to straighten it but decided I was more likely to damage it so left it alone. Perhaps an indication of the level of force that's been applied to get the hand brake to hold the Sprite on slopes.

Colin
C Mee

I thought the point of having a thread in the first place was so that you can adjust the handbrake cable.

If you undo the carrier it will offset the cable stretching over time.

Other than that I couldn’t imagine much movement other than minor lateral twist against the thread when applying the handbrake.

What is the other reason for being able to adjust the carrier along the thread?









James Paul

Am I missing something, isn't it pushbike mechanicals, the cable slack is adjusted by the thread and nut at the end of the outer cable sleeving thingy-wotsit, held by the bracket and second nut.

I can never seem to get any grease into that thing, am I the only one to fail?

I once took the nipple off to test it went through the nipple and it did and the grease below the nipple inside the thing looked clean but the grease only ever comes out of the side of the grease gun connector, every 6-months or so, just for the joy of getting clean grease on my hands to help clean off the dirty grease, wot fun.
Nigel Atkins

The maximum leverage given by the "tree" is when the two arms make close to a right angle with the handbrake rods. The adjustment is therefore most effective with the arms slightly before that right angle, so that as the handbrake is applied it moves through to that maximum leverage position as the shoes come into full contact.
GuyW

Nigel.
You are correct about adjustment. The handbrake cable is adjusted by the two nuts.
To 'shorten' the cable the outer sleeve is lengthened between the two fixed points and vice versa.

No more do I have grease escaping between nozzle, on my Wanner grease guns, and the nipple (zerk). No more interposing a cloth to seal the joint. I have invested in collet type grease gun nozzles that lock onto the grease nipple and seal the joint so that all the grease goes where it is supposed to.
Alan Anstead

Thanks Alan, I'll have to see if I can get a collet head for mine, I thought about it before and forgot.

The gun I have works on the other 7 nipples (mostly) and 6 of them were replaced this year (which reminds me I meant to grease them about now). Its just that tree nipple I can't remember having any more success with the previous gun hose or different guns. Perhaps it's just already full or has always been blocked, not to worry the tree seems to work.

That nipple is pain to get at too as my one-(oversized)-handed gun has to fit between the exhaust so is great fun to try and fail on that nipple every six-months, but I persist.

The other handbrake nipple puts a snake of grease down the transmission tunnel as I discovered once when I pushed on something black to see what it might be.
Nigel Atkins

James

Thank you for the close-ups of your hand brake compensator. I never realised there were meant to be felt washers on the clevis pins until I spotted yours. I now have a set for both ends of the handbrake rods on order! Perhaps they will make my Sprite a tad quieter by reducing the rattles.

Also, the horizontal thread supporting your compensator appears to have the same slight bend that mine has so maybe mine isn't distorted. Your photo suggests that the bend aligns the compensator so that the handbrake cable pulls straight and not at an angle.
C Mee

Nigel
On my Wanners I swopped the solid hose for flexibles: easier for getting into tight or awkward places. Once the collet is locked onto the nipple it is a one handed operation.
Alan Anstead

I do not consider felt washers to be particularly durable so have made replacements from leather for fitment to bottom of balance lever (2K5820) and clevis connections (6K690 & 2K5291). A special concentric punch was made for lever but others were cut freehand using a set of jobbing punches.
S G KEIL

Alan,
I took the solid pipe off mine as made it getting under the front of the wheel arch valence area tight but the flexi-hose has the same effect with the gun clattering against the inside metal as I try to push the head on and overstretch my hand to start the pumping.

I had a really nice full size cartridge gun with good applicator on it but I gave it to my neighbour decades back with a nearly full cartridge of (green) Slick-50 grease and forgot about it. I saw it in his garage a few years back but I couldn't ask for it back as he'd have forgotten it wasn't his.
Nigel Atkins

The felt washers now aren't much cop, I got some a couple of years back but just left the old ones in. I'd have thought anything durable that cushions and prevents the metal on metal clanking would be fine.
Nigel Atkins

This thread was discussed between 24/10/2021 and 09/11/2021

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