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MG TD TF 1500 - rear brake drums
|I recently removed rear brake drums during routine service and found the upper brake lining has no drum contact witness marks all the braking is relying on the lower shoe. I thought at first the hydraulic wasn't sliding up when pressure applied, I then found that although the cylinder was rising it reached the top of the slot before the upper shoe was contacting the drum so no braking via the upper shoe. as the linings were new when fitted some 500 miles ago my thoughts go to worn brake drums. does anyone know the internal diameter size as both my drums measure 9" it seems this can be the only answer to my problem. the hand brake works perfectly considering there is only one shoe in contact with the drum on either side.
Your comments regarding drum size will be much appreciated MGTD 0845
|I think it was one of the John Twist videos (University Motors) that described how to add a "penny" (not sure how big an American penny is) under the snail Adjuster to accomodate worn 'unobtainium' brake drums. |
I did something similar (welded a piece of steel under the adjuster) but I am unable to really test their effectiveness as I have a barely rolling chassis.
|C I Twidle|
|I followed this video by John Twist to correct a similar situation with my TF.|
More info in this thread and alternative solutions in this thread:
|One other possibility Twist does not mention: many of the repro cylinders are a very tight fit in the backplate slot. They must move freely up and down, and make sure it moves upward (opposite from the piston) as far as an original cylinder. This may take a little hand fitting, but is crucial. George|
|Drums are 9" drums, but should be measured with a brake drum caliper, as just a few thousands off can make a difference.|
|The standard Moss T series drums for wire wheels I recently bought for my 4.3 axle conversion are stamped "Max Dia 230mm". That's 9.055 inches.|
This is the only written specification for a drum turning limit I have seen.
I measured my old rums with a 12"dial vernier, not absolutely precise but you can get a fairly close idea of drum size. (probably +/=.005").
|T W Moore|
|I think it was one of the John Twist videos (University Motors) that described how to add a "penny" (not sure how big an American penny is) under the snail Adjuster to accomodate worn 'unobtainium' brake drums."
The problem is not so much the diameter of the rear drums as it is that the rear brake cylinder is a sliding mount, so it requires twice as much pedal travel than on the front brakes where there are two cylinders, so each shoe only has to travel half as much as the shoes on the rear brakes have to. I purchased (and I don't remember where) two masks with a strip of 1/4 by 1/4 welded on the seats of the of the masks.
|Is it possible that the backplates are on the wrong side of the car. The slot for the brake cylinder is displaced about 3/32" in relation to the bolt holes and would not allow full travel if on the wrong side.|
I can't remember if they are marked L/R like the fronts.
If you have your rears powder coated make a blanking plate to cover the slot as the paint will jam up the slider springs and you will not be able to fit the cylinder.
Ray TF 2884
Adding a spacer under the adjuster WON'T solve your problem. This spacer fix is only to anable you to correctly adjust the shoes with the piston at rest.
In your case the wheel cylinder is prevented from moving far enough upwards with the piston under pressure. You need to investigate why the cylinder cannot travel upwards sufficiently for the upper shoe to press against the drum.
|Excuse the typo, anable should be enable.|
|Thanks for the info, as stated, fitting spacers to the adjusters wouldn't make a difference as the problem is the cylinder reaches the top of it's travel before the top shoe contacts the drum. As I rebuilt the car 15 years ago I had all the parts in this area powder coated and could have assembled the back plates wrong way about as Ray suggests. I will now strip the back plates and look for L/R and check the dimensions and report back to you.
Thanks again for all your inputs and expertise.
Kind Regards, Adrian Wells.
You should find the markings behind the upper shoe and slightly to the rear. If you had the plate powder coated then they may not be visible.
|I don't know what happened with the re-posted thread but it seems to have cocked things up.|
|I brought the thread problem to the attention of the Webmaster. Bud|
|When the plate is on the correct side, the anti rattle spring plate (B) is to the rear of the brake shoe rest bump (A).|
The photo belongs to LaVerne Downey.
Ray TF 2884
|in case it is not clear, the photo shows the it on the wrong side. |
See archive "brake back plate"
|Result. when checking back plates as Ray suggested they were wrong sided the number and l/h r/h were clear. so they are now correct and have top brake shoe contact when I lift the hydraulic up, great news this is the reason the brakes were rubbish when I reversed.
The problem now is, when I removed the hubs to removed the back plates I found a lot of play in between the half shaft and hub on one side, it seems the wear is in the hub more than the half shaft. Does anyone know where I can buy a hub from or does anyone have a spare they no longer need. my contact number is 01522681235 Lincoln UK area
Thanks again for everyone's valuable help.
Regards Adrian Wells.
|New hubs are available from Orson Equipment in the UK. http://www.orsonequipment.co.uk/splined-hubs/|
|Thanks Lew but my wheels are solid not wire I think the address you sent only make for wires.|
|Orson claims to do anything, so although only wire wheel hobs are shown, it might at least be worth a call.|
|These folks that you posted, Lew, sound like a really good potential supplier for steel wheel brake drums for the TD. From their website:
"Brake Drums & Discs
Orson Equipment has been producing brake discs and drums for over 40 years. We have a range which are produced for a number of cars. Orson Equipment are the leading name in the supply of brake drums for Jaguar XK120, XK140, XK150. In addition Orson also produce drums for Allard, Aston Martin, MG.
Orson Equipment produce a range of brake discs for Jaguar XK conversion kits. Orson is the only British manufacturer of the XK conversion disc.
Orson Equipment has a reputation for the remanufacture of Discs and Drums for out of production or no longer available hardware. Working with the client from worn or broken products Orson Equipment has been able to remanufacture a number of discs at reasonable cost.
If this service is of interest please contact us directly. mail to: firstname.lastname@example.org "
|I've dropped them a note... I'll let everyone know what I find out.|
|I found Orson Equipment a few months ago while browsing. I liked the fact that they were a specialist UK engineering firm with a strong focus on splined hubs and knock off spinners for classic cars. Their web site tells us they have been in the business since the 1970s.
After some correspondence I ordered sets of both hubs and spinners all round. They were a bit slow responding to emails a couple of times but were nevertheless very helpful. The items were well packed and arrived in an appropriate time frame. I think their prices are excellent and from what I can judge the quality is also excellent.
I was very pleased to see that their spinners correctly say “UNDO -> RIGHT (OFF) SIDE”, ie they don’t say “UNDO->UNDO” like most other after market offerings. (I would not have bought them otherwise). They have the central MG logo.
PS No connection with Orson other than satisfied customer.
|M R Calvert|
|Well, they responded very promptly to my email. Here's what they said:
We do supply the MG TD Brake drum. The one we make is in the picture attached. This is the one we supply for Wire wheel cars. These are £88 each – and we have 7 in stock.
We can manufacture the drums to suit steel wheel cars. We would need a pattern to produce the tooling for the casting. If this is of interest please let me know.
All items manufactured by Orson Equipment are made in our UK factory. Orson Products are of ORSON Manufacture. Important Notice : We have a change of address.
Tel : 01902 906290
Sooo... it sounds like if there's interest in producing a run of rear drums for the disc wheel TD's they're game to do it. Shouldn't be hard to find a drum/hub unit to give them as a pattern.
|The second photo they sent me of the wire wheel drums they make:|
|What about also doing new front drums for TD's with steel wheels?
I should know this already and could take them off the car an inspect them to see but what is the difference between the front and rear brake drums? (for the original steel wheels not wire wheels) I see in some supply catalog that they are different part # but in the parts explosion illustration look the same.
I'd be interested in replacements all around at $117/88# per drum. Cheaper than spending $1500 on the front disc/caliper conversion at and still have the backs to deal with.
Seems like there would be a great replacement market opportunity.
|I have a pair of rear brake drums that I think are for a steel wheel TD. I'll take a photo tomorrow so that you can check if I am right.|
|Randy - front and rear drums are completely different: the front have bearings and seals inserted to fit onto the stub-axles, the rears are splined without bearings, to fit the axle shafts.|
|These are my rear drums.|
|The octagon car club sells new front drums, price seems right. Transport cost to the US will be high because of weight.|
|The Octagon MG Car Club will usually not send parts to the US. I believe they think we are a litigious society and will sue them at the first hint of a problem. If anyone has had any luck getting parts shipped to the US by the OMGCC, I'd like to know how you did it.|
|Ok, so here's my answer (and reply) from Dave, after the dashed break line below.
So, I'll ask all of you... Do you think we have enough people here who want a new set of rear drums to make this worthwhile? (Admittedly without a price that's hard to judge, but chime in if you might want a set so at least we have some idea.)
Thanks, Dave. Yes we likely have U.K. folks with spares they can loan. I've polled the group to see if there's interest and I'll let you know.
On Sep 14, 2017, at 1:30 AM, Dave Wood wrote:
Interesting. I cannot really get a price for the casting without either a drum or drawing to measure against. I would need some dimensions to work with – or is there a guy in the UK who could loan me one?
Machining is not too much and I suspect I have the broach for the drum. But really need a sample. Let me know what the forum thinks.
|I would buy a set (all 4 drums) if available and good quality; and also willing to place a deposit. |
Did they say the number needed to make them?
|Ok. My spare drums are potentially available to Orson to assess and make drawings from, but I agree we would to indicate the level of interest. The desire for replacement rear drums has been raised many times on this forum and elsewhere, so it has to be at least a few dozen (?). |
|They did not, Bill. And Dave, thank you for your offer! We'll see how many folks pony up here to want a set, and then perhaps we can send off your drum to get an estimate?|
|Hi David Hill, as my TD is the early type my rear drums and hubs are separate same as the front but the combined hubs and drums are compatible. Would you like to sell them to me.|
|No inclination to sell at the moment, but would lend to Orson for measurement. |
I would consider ordering a set front & rear.
|So... not a lot of takers so far? |
I'll start a thread with a more relevant title and see who jumps up.
|I would be interested in a pair of rear drums|
|OK, so at the moment there are no rear hubs/drums available. I have replaced the worn hub and used a new 7/8" UNF and tighten very tight, a 2ft ring spanner and 13 stone, bouncing to the nearest split pin hole, driven forwards and reverse with no clunking so all seems well.|
Thanks all for your input and experience all very valuable.
Kind regards Adrian Wells TD 0845
|I would be interested in front and rear drums.|
This thread was discussed between 28/08/2017 and 18/09/2017
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