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MG Midget and Sprite Technical - Brake shoe thickness
|Okay so after replacing the rear oil seals I now need to reassemble the brakes.
All new components used apart from adjuster.
Handbrake lever arm
Assembled it all on the backplate off the car for ease of fitting the cylinder, then bolted it on and refitted hub.
My issue is that the drum will not go on. Or rather it will with some rubber mallet action, but even with the adjuster backed right off for zero effect, the shoes and drum are in very tight contact, and even with a wheel fitted it will not turn readily.
Double checked everything was seated correctly. Still tight.
Refitted old hand brake levers. Still tight.
Refitted old springs. Still tight.
Refitted old shoes, drum turns freely and you can even adjust it up.
Didn't pay much attention to the new shoes before this, old one were under the car somewhere.
But when comparing them they are noticably wider (not sure if that is an issue given that fitting wider Mini shoes is a thing), but the friction material is much thicker. approx 5mm.
Old shoes are obviously worn but they have done only a few hundred miles at most.
What sort of thickness is this material normally?
Picture showing new shoe on the Left ...
|Picture showing difference in width. On closer inspection the differences don't end there, the lining material is 'longer' (goes further round the curve) too.|
|They don't look right at all, do they! What brand are they, and who supplied them? Got a pic of the numbers on the box?|
|They were from a Classic Car supplier in Sussex ;-)|
No brand name, label reads
RGBS834AF (which certainly seems to be the correct number)
midget RR 1963-80 Shoe Set (LS1415)
And (perhaps the cause of all the problems) Made in Taiwan ...
Cant see any numbers on the shoes themselves.
|What about fitting new shoes with old drums. that might give you enough clearance. I wished I'd kept my old drums new ones had high spot and no cast marking numbers.|
Only the other day I deleted the photos of my new (Mini) shoes compared to the old Spridget ones but neither were as thick as those.
|Nigel, the trouble with that is that they're wider therefore will pick up on the wear ridge at the outer edge of the old drums..|
G- -send them back!
You want a decent brand like Mintex or TRW or even Delphi, in the proper box.
How about these - https://www.ebay.co.uk/itm/121767695417
|Sorry I was looking at the depth of lining and didn't notice the width.
In fact, sorry I missed the post with the photo and saying they're wider and longer - perhaps suggesting they're the 1.5" but they should still fit inside the (new) drum if that were the case. Those must have wrong depth of lining.
I remember now I was looking for the photos I deleted of brake shoes, as I have back-up files see below, 1.5" and 1.25" and difference in lining length on different makes of shoe.
ETA: David I've confused you too now, eBay link goes to Mintex front pads.
|That link is for front brake pads, but yes something branded would be preferable.|
Going to pop to Somerford Minis tomorrow which is just down the road from me and see what they have got in stock. Might be the only way to get the car on the road again for the bank holiday.
I did actually come across those photos in the archive whilst searching for a possible solution.
|Why didn't I think of that.|
I got the wider Mini ones to perhaps help balance out the front upgraded Mintex 1144 pads which I think they did but the braking wasn't that far out anyway.
Good tyres that aren't hard from age and/or lack of use regardless of tread depth left help braking no end.
The force due to friction is generally independent of the surface area so wider/longer pads of the same composition shouldn't give increased braking, just longer lasting pads. Change the composition and anything is possible.
|Those shoes just look wrong.|
Send them back.
|Dave O'Neill 2|
|Just had a chat to my old neighbour who owned a brake business years ago|
He laughed and said that they have probably glued early front drum brake linings on rear shoes
Apparently the fronts are 1mm bigger diameter and unless the rear drums are worn or have been machined they'll never fit over the larger front linings
send em back
|hmmmm the link I posted is a mystery! Here's a correct one: https://www.ebay.co.uk/itm/303142465870|
|Don't forget Kim at Magic Midget is just on the outskirts of Melksham, if he has any in stock they will be good ones.|
|Just been to Somerford Mini (literally 5 minutes from me) and picked up a set of Mintex shoes for just over £13.
Chap was happy to break the box seal (he offered) to compare to the ones I took with me.
Interestingly the friction material looks to be just as thick as the non fitting ones (give or take a gnats) so I shall pop out now to fit them and report back.
I had forgotten about Magic Midget. Only time I tried to contact them via email a few years ago I never got a reply. Don't know if collection is an option, I begrudge paying delivery from a few miles away!
I think Kim goes away a bit but can be contacted, the problem with leaving messages (like this very post) is that you don't know if it gets there or to the right place. I've had two emails recently not get through and very delayed.
IIRC other people have collected parts from Kim, a great guy to deal with, worth the effort.
yes good point, I do remember you explaining that more fully before, I should have added what you put (not that I'd have put it so succinctly).
|Okay.The replacement shoes fit …... better
I'm still not happy that there is so much binding though.
This time with the adjusters backed right off you can get the drum on without much force. And you can no longer do up the wheel nuts tight without the wheel spinning.
But the amount of friction just seems too much. More than I would normally adjust back to when doing the handbrake.
Should I just do the other side, bleed it all up, and take it for a careful drive to bed stuff in, or have I done something wrong in my reassembly of the Hub, bearing, brakes that could be causing the issue.
How loose a fit should an unworn drum over unworn shoes be??
|Modern new shoes often require the square ends of the lining material to be eased or relieved a little bit with a coarse file. They also frequently benefit from having the web ends dressed a little to fit correctly in the slots. You might find it worth a careful look to make completely sure they're not interfering there.|
Actually, not just modern shoes - it was always so, depending on the quality.
|Fit both sides and then stamp on the brake pedal a few times to centralise everything, they should then be in the correct position and be a non-binding fit, but may still drag a fraction. In that case what grey said is all good advice too. Lastly (or firstly if I'd thought of it!) check the handbrake cable isn't adjusted up too tight and causing the binding.|
|To take the handbrake out of the equation you could take the pins out to completely uncouple it from the arms, and I'm not sure if or how much difference fitting the arms other way round would make by it might add just enough added to tightness elsewhere.|
|Handbrake has been disconnected the whole time as I was renewing the levers due to VERY worn pin holes.
Well I have just fitted up the 2nd side. As far as I could tell the bearing seal was not leaking this side just the end oil seal so just fitted a new o ring and gasket.
Also have not swapped the brake cylinder this side yet.
Just fitted up the newest shoes, springs, levers and the new drum. Much the same as the other side (although I noticed some of the tightness in the drum when fitting this side was the new shaft seal gasket protruding by the stud holes, this was duly relieved with a sharp blade. (note to self Check the other side)
As it stands now (both wheels in the air) using a small hand sprung scale, I can pull almost exactly 9lbs at the end of a standard ratchet handle on a wheel nut each side before the wheel turns.
So both sides are much the same which is something.
Have not adjusted the handbrake up yet, both sides are fully off, yet I'm only getting 3 clicks.
I shall fit the 2nd new cylinder, bleed it all, take some edges off the pads, and take it for a gentle drive up the lane ... but not today. And probably not this weekend either :-(
Thanks for all the advice. I shall report back at some point in the future.
|Presumably you do have the adjuster centred on one of its flats?|
|At the moment both adjusters are backed right off and the little wedgey bits loose.|
|Too late now but a photo or two of your installations might highlight something to someone.
Sounds like you've already research the Archives and seen photos and drawing of installation, if not I can put some up here.
I've never been sure that the handbrake levers are sold as correct sides and if they should be other way up as there angle out of the backplate of the drums never looks quite right to me but I don't think this is your probably as they're not connected.
As I had a highspot on one drum (and no lathe!) I drove about 40 miles stopping regularly to loosen or tighten the adjusters as required by how warm the drums felt and this got it good enough not to worry about.
|Yes I've bled the archives dry ;-)|
Currently at the stage of fitting 2nd cylinder and contemplating pulling the hub anyway just to take the backplate off and fit that clip on the bench!!!!!!!!!!!!
get a small machine screw, fit the cylinder using this screw in the bleeder thread, this will leave you with both hands free, place the E-clip on by springing the tangs with a suitable sized screwdriver and then space and test the E-clip with the screwdriver.
Note the red lines in below for correct facing of E-clip.
There's also a slight indent on axle but it depends on the E-clip if it'll go there.
The correct Bellville washer (as well as circlip) for rear brakes for front disc braked cars available from AH Spares: https://www.ahspares.co.uk/sprite/brakes-xbrk101-to-xbrk210/ (see drawing item numbers 65a & 65B). AH Spares have reproduced these special Bellville washers that had been NLA for a while.
Tool similar to the above one for fitting these clips: http://www.minispares.com/product/Classic/Accessories/Tools/TOOL14.aspx?0108&ReturnUrl=/search/classic/Tools.aspxBack%20to%20search
Got both sides together and went for a drive yesterday, just up and down our lane.
Handbrake has never had just short travel.Foot brake lots of pedal movement on first press, much better on second press. To me does not feel 'air in the system spongy'.
First thing in archives to check, rear brake adjustment.
Whipped the drums off again this morning and investigate.
First thing I notice is that the shoes are not touching the brake cylinder as they are being held off it by the handbrake mechanism.
Remove the rod-to-arm pin and the brake shoes spring back, but now of course the rod does not reach the arm by getting of for 3/8". Much the same the otherside.
I guess the old arms had a lot of play in them and the holes were definitely very worn.
As I see it the only way to get the arms back out to the holes is to adjust the cable when it meets the lever thingy (some say christmas tree?) on the axle.
Not difficult. But when it is adjusted far enough for the rod/arm holes to line up, it is no longer at right angles to the cable or the rods which the archives hint at being the optimum angle.
I also notice that adjustable rods are a thing, but that seems to be fixing something that should not be necessary, after all my rods have not shrunk in the 30 years I owned the car.
So I'm not sure what to do.
I could lengthen the rods, modify the arms or both, but that seems counterintuative.
Does anyone have the lengths of the rods to hand (steel wheels, I've read the wires have shorter ones?) or any other suggestions?
|The right, "right angle" at the Christmas tree is a detail that is often overlooked so it's good that you are trying to observe that. The optimum is for the rods and lever arm there to form the right angle as the handbrake is just reaching its full pulling force on the brake shoes.
I don't know if that makes a difference to the adjustment you are managing to achieve?
Also, you really need to use the car for a few miles before you can expect to be able to get the best justment. A 100 or two should be enough after fitting new shoes and drums.
|The handbrake cable is adjustable at either or both ends; maybe adjusting at the bracket at the back of the tunnel will improve matters.|
The steel wheel handbrake rods should be 14 3/4" on the left, and 26 3/8" on the right, measurements taken between hole centres.
|As I put in a previous post a photo or two of your installations might highlight something to someone.
I've never been sure that the handbrake levers are sold as correct sides and if they should be other way up as there angle out of the backplate of the drums never looks quite right to me.
You put new arms and springs are they fitted correctly, copying what was there before isn't necessary correct even if it was working.
Is the handbrake cable stretched, did you disconnect or adjust this? If the h/b cable has a reasonable amount of adjustment left in it then it should be quite easy to overtighten the adjustment making the handbrake lever set too low from raising it.
Does the lever tree for the rods move easily not stiff, been greased at same time as h/b cable at services (though I never seem to get any grease in the rod tree lever).
Are there other clevis pins or the holes they go into worn?
Shoe fitting, just in case.
|I've been trying to get a decent picture of how everything is fitted but my phone has decided not to flash and I can't get the lighting right for a clear image.
I am however 99.9% sure the shoes, springs etc. are all fitted correctly.
The research I've done suggests the levers are on the correct side, though as said the angle could be better.Up the other way though the pivoting bit would be bearing on the spring which cant be right.
The lever tree is free to move, nicely greased, but may have too much 'wobble'. The holes are worn (but not in the rod ends) and if they were all tightened up by what ever means there would be less likeyhood of the rods reaching the brakes …
Thanks David for those measurements I'll have a check tomorrow and see what I have.
At the moment I would not want to do 100 miles with the brakes as they are, far to little result on first press.
I shall have another look tomorrow.
|Just re-read your earlier -"the shoes are not touching the brake cylinder"
This seems odd. Even if the handbrake lever is supporting the shoes in that position, then the cylinder pistons should still protrude enough to be in contact with the heel of the shoes. If not, then what is retracting them to that position? And more significantly, they will have to move a distance before the shoes begin to move so that will be lost travel at the pedal and will also make the front brakes far less effective.
Maybe I am misunderstanding your description?
|Might just be me but the photos the suppliers use that I've seen for the h/b lever arms seem opposite, i.e. the RH is actually the LH and visa-versa, or is that just me.
I have a special repair kit for these fabulous electronic mobile devices!
I use a couple of old digital cameras.
Possibly the problem isn't (just) with the brakes but I can't think what, certainly the adjuster would normally need screwing in a bit so that sounds odd and it was the h/b lever arms holding the shoes off the cylinder until disconnected that made me wonder about them and the h/b generally.
|Guy yes I was wrong on that front.
I did actually remove the handbrake pins before removing the drum, then thought it better to leave them in, so popped them back. Presumably doing that allowed the springs to shove the pistons back in, showing up as a gap after drum removal as I had not pressed the brake pedal in between.
I have check a few times now (god knows how many times the drums have been off and on) and the shoes appear to be properly seated at all times.
Sorry about that misleading bit.
Rods measured this morning and they match Davids measurements, thanks.
Adjusted the hand brake cable so the rods would fit them arms without pulling the arms out and as suspected the 'tree' lever assembly is not really at the angles described.
I'm sure there is a happy compromise somewhere, but to me having to pull the hand brake arms out 3/8" to meet the rods to fit the pins and thus having the cylinder pistons start their movement already part way out (once 'pumped up') does not seem right. Maybe I'm wrong?
My interpretation of adjusting up the shoes is that it should be done with the hand brake disconnected, then attach the rods. I cannot do this in the above situation (arms will obviously not move out), only if the cable is adjusted and the 'lever tree' angles are not how Guy describes (I think)
So longer rods? Modify the brake arms.
Leave it as it is now (wonky tree) and road test it again.
I'm going for the latter at the moment, but have had another issue jump out at me now. Thought I would bleed the rears again whilst it was up in the air. Stuck the Ezibleed on empty just to test the seals (I usually do this as a matter of course), tyre at 18psi, all good. Fill with fluid, and reconnect. Disappear under the NS rear wheel arch, when there is a loud hiss and what initially looks like smoke from under the bonnet.
Bottom seam of the Ezibleed bottle had split along the mould line and emptied the whole bottle of DOT4 over the engine bay, inner arch etc. and it was running out of the wing/sill gap.
Got the rear wheels on ASAP, dropped it to the ground and rolled it outside to run a hose over everything :-(
Oh and some pictures for Nigel.
No I've not angled the shoe edges yet, can't find my big file.
|And the hand brake tree, sorry one is fuzzy.
|ETA: typing whilst last photos went up.
Sorry to hear about your problem, I've had so, so many 'disasters' with various cars over the decades I know how you might feel, have a short break and remember in the end it's just a lump of metal and not really that important overall in life, it really isn't despite how we feel about them.
The potential of a blow out for me as only usually have 'bad luck' with cars is another reason I'm not a fan of such (yes I know it's rare, check equipment and so on) I'm a very simple mind so like very simple systems.
The photos are not really for me as I don't know enough but I was still wondering about those lever arms and perhaps rest of h/b (but could be wasting time on this).
Having the tree lever at ideal angle is best but not essential to get some h/b holding, this could be sorted later if required.
Just recently I had to flush through the clutch (again! third time in less than a year) and I have wet/damp microfibre cloths all over the wing and under the master cylinders, with a washing up bowl and watering can of water and hose close to hand. OTT I know but I've still before managed to drip brake fluid on unprotected paint (bloody bonnet prop gets in the way).
I use the slow, and patience and time required, one man and a jar (closed/immersed) method usually as it's easy and I don't need a (very unwilling) assistant - literally no pressure as such.
I've tried different suggested and written methods of adjusting the rear brakes and provided you adjust all that's required I've not found any difference in the end result. Provide there's not a huge difference then the h/b setting will need some adjustment after fitting new parts, all the different little areas of wear can add up to a surprising amount overall.
|Brake tree doesn't look that bad. I wonder if the h/brake cable had been adjusted too much to take up wear in the rods. I'd go for adjusting the brakes without the rods attached so you get a decent pedal and then connecting them up. Bad luck with the ezibleed hope the fluid washed off ok.|
I'm going to try it again as is and see whats what.
Then I'll be searching the archives for solutions to worn pedal pivots.
Whilst I had my head in the foot well 'mopping up' I had a wiggle of the brake pedal and the pivot bolt head (or nut maybe) at the clutch end, had quite a bit of movement in it …..
|Difficult to tell at that angle of photos (I can't see much difference but that might be me) photos from side of car through wheel arch might show more.|
I'd be interested to see h/b arm lever from axle side - but that just me.
How many h/b lever clicks was it to on?
|2 cents worth-
Just looking at that pic of your handbrake tree--I don't know what's in the book, but looking at it purely as a mechanical linkage,
To me it looks to be in the perfect position as is-
The pull lever that has the cable connected to it appears to be at roughly 90deg to the cable line which gives maximum mechanical advantage there
The levers that the rods are connected to appear to be back approx 30deg from rightangles to the rods, this in fact increases their leverage advantage on this pulling side of the tree
I'd be more than happy to have it all sitting like that
If you were to fabricate longer rods to get the tree at rightangles there will be a loss of leverage advantage there and also the cable lever will be around past 90deg with the cable causing a loss of advantage there as well---I'd leave it as is if it were mine
The normal way of adjusting brakes is always let the handbrake right off, adjust the shoes, THEN connect and adjust the handbrake
From then on the shoes can be adjusted at any time without de-adjusting the h/brake as it has been set in the correct position to suit the shoes/drums which should only need doing once until a component is changed
|Nigel, 5 clicks.|
I shall leave it I think, and try and get a few miles on it.
I'm more concerned with getting a good foot brake than a super efficient hand brake at the moment...
|Looking at the pics of the axle the handbrake lever seems to be jammed up underneath the cylinder - could be the angle of the pic ? also the end of the spring usually goes into/against the drilled hole in the handbrake lever - as per Nigels diagram.|
Is the H/B lever correct for fitted side (I assume they can be installed on the wrong side) ? which would have the effect of raising the cross bar.
|Lever is definitely the right side and clear of the cylinder.|
I have actually bent that end of the spring to sit against the lever better since taking that photo.
Just been for a quick spin and I think there is an improvement. Can lock the wheels on a first hard press of the pedal now, although it still seems 'long' and does get better on a second press.
Pivot bolt issue solved by tightening it up!
|After having disturbed the brake shoes and drums I alwayd adjust the brakes so there is a slight drag when rotating the wheel by hand. Any more slack than that and pedal movement goes too far to the floor for my liking, and the front brakes are far less effective. However, when set like that if I jack the wheels up and check again after just a couple of miles they will already spin a bit more freely as they align themselves. So my advice is when adjusting don't be afraid to tighten the adjusters a little more than just free running.
Just to add, this is in addition to stamping on the foot brake pedal a few times to align the shoes when first adjusting. That helps get them set right, but it's not the whole process. A bit of road use is needed as well.
|Just as a bit of closure to this.|
Got a refund through for the odd shoes a week ago so thats good.
Sat and tried the pedal of someone elses car (thanks Andy) and it seemed only a little better than mine.
Whilst it was sat in the garage having the head gasket done I readjusted the rear brakes as Guy described above
Gasket sorted, went for a short drive today and the pedal is much better and more confidence inspiring.
This thread was discussed between 02/05/2019 and 01/06/2019
This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.