PXC Posted January 31 Report Posted January 31 Hi everyone I always thought my front brakes needed an overhaul because I could see significant (so I thought) rust and pitting on the discs, and assumed the pads would need replacing (since I bought the car in 2024). Also the pitting was mentioned on the last MOT test (April 25). so at the TR fest bring and buy, last summer, I bought a pair of slightly used discs for £25. Today I started the strip down, and found that not only do the pads look fine - at least 10mm of material on all 4, no uneven wear, but also the discs look relatively ok, slight grooves and uneven wear on the offside disc but thickness of disc about 12.5mm. But some rust and pitting. The nearside is better. Compared to the pair I bought, which overall have a smoother disc surface, the replacements are marginally thinner than the ones on the car. I am tempted to keep the existing parts on for another year? Any recommendations? Regards Paul Ps - the calipers were refurbished by the PO. pps. I don’t actually have a problem with the brakes, pulls up straight. But I thought it could be stronger (although maybe falling into the trap of comparing with my modern car). Any problem may lie with the rears which I am next going to examine Cheers Paul Quote
RogerH Posted January 31 Report Posted January 31 Hi Paul, any pitting will reduce braking efficiency. Your discs look very pitted. If it was me I would buy new discs. Roger Quote
PXC Posted January 31 Author Report Posted January 31 And new pads? Or will the pads bed in to the new discs? Quote
RogerH Posted January 31 Report Posted January 31 New standard pads are quite cheap so worth replacing. However do consider better quality - Ferodo, Mintex etc. Roger Quote
PXC Posted January 31 Author Report Posted January 31 Ok thanks Roger. Wheels back on while I look at the rears. But now I know with new parts, it’s probably only an afternoon’s work to replace the lot. 👍 Quote
rcreweread Posted January 31 Report Posted January 31 I've got some original 10 13/16ths" diameter discs which I've had refaced which I will be taking to Stoneleigh - £17.50 each. I've also got some new standard discs which are £22.50 each Let me know if of interest I'll be on Stand 330C in Hall 2A Cheers Rich C-R Quote
Trev Good Posted January 31 Report Posted January 31 If your discs are thicker than the replacements, get them skimmed! Quote
iain Posted January 31 Report Posted January 31 Replace the discs or skim, replace the pads and also the pad retaining anti rattle fittings, they look shot. I use Mintex Classic pads, good braking performance, and extremely durable. Poor rears do have a big impact on the sidescreen cars. I tried, 9” rears ( being easier to get and cheaper) on my car which has always been on 10”……..notable difference and not for the better in my opinion. Iain Quote
PXC Posted January 31 Author Report Posted January 31 Thanks Rich C-R. My current discs are about 12.6mm to 13mm. I can’t find a spec (not in my documents) for what thickness they should be? also, if new ones are only £22.50 each, I can’t see refacing them is cost effective, unless you DIY. Paul Ps anti rattle fitting are indeed shot! Originals probably Quote
rcreweread Posted January 31 Report Posted January 31 Paul - my refaced discs are £5 cheaper than new ones and are original ones so quite possibly the quality of the steel is better - the guy who did them for me has a contract to reface discs from the Addison Lee taxis and typically does 1000 at a time! Cheers Rich C-R Quote
PXC Posted February 1 Author Report Posted February 1 Ok I’ve now got the rear wheels and drums off. They are 10”. the drums are smooth and shiny with no pitting or grooving, and the shoes look like they’ve been replaced at some time. it’s had new slave cyls as well, they look clean and no leaks. So, only question is do the shoes need replacing? The depth of friction material is about 4.8mm on both sides. What would new ones have? i should mention that I don’t have a problem per se, this was just exploratory (never having had them off in my ownership before). Exception is that the rear offside stays stuck on after handbrake released until I start reversing out of the garage, then it unsticks itself with a loud click. However, having seen the clean inside, I’d hazard a guess that it was just a bit over adjusted. I’ve backed both adjusters off 4 quarters just to aid refitting the drums. Quote
Chilliman Posted February 1 Report Posted February 1 Looking at those pictures Paul, I think the only thing your car needs is using. Quote
dwaters Posted February 2 Report Posted February 2 Paul, I think there should either be shoe steady posts or shoe retaining pins fitted, depending on your commission number. The holes in the shoes don’t always align with the corresponding holes in the backplate, perhaps this is why a previous owner hasn’t fitted them? David Quote
Lebro Posted February 2 Report Posted February 2 (edited) Agree, should a pin coming through a hole in the backplate, then throught a hole in the shoe, it has a flattened end, onto which a spring & a special washer is pushed, & twisted (bayonett styule) to lock it on. It prevents the shoe "falling " outwards away from the back plate. Lack of them bay explain the "click" you talk about when reversing items 127 - 129 Bob Edited February 2 by Lebro Quote
Lebro Posted February 2 Report Posted February 2 (edited) Looking at your photos, you have plenty of lining material left on those shoes, they don't look worn at all. So, unless they are soaked in oil / brake fluid not uncommon !) they will be fine for many many miles. Bob Edited February 2 by Lebro Quote
PXC Posted February 2 Author Report Posted February 2 1 hour ago, Lebro said: explain the "click" you talk Also explains why the shoes pull outwards making it difficult to remove the drums. Quote
Ralph Whitaker Posted February 2 Report Posted February 2 Been looking in original workshop manual and there is no reference to the original thickness of the discs, only reference to no more than 0.060" to be removed if they are being "trued up". I am assuming that they were originally 1/2 inch (12.7mm) and your 13.07 measurement was either a build up of rust or a slight discrepancy in the measurement. So 60 thou being 1.5mm, anything over 11.2mm should be OK including the replacement discs you already have. Remember too that the TR3 was one of the first cars to have disc brakes and the discs were quite thick compared to later cars, for example the discs fitted on my Dolomite are only about 10mm thick from new in a car of similar weight with servo assistance, even the Sprint uses the same discs as my lowly 1300. FWIW I have skimmed discs fitted on my 3a. Your rear brakes do not even look bedded in yet, the pic of the offside shoe shows the only contact seems to be the last couple if inches before the adjuster. It might be worth checking the backplate as it is common for the handbrake lever to wear a notch in the back plate which prevents the cylinder sliding back and forth as it must to obtain proper braking on both shoes, though this normally means that the trailing shoe does little work and the shoe directly operated on by the piston in the cylinder does most. If the backplate is grooved then it needs welding up and grinding flat again. Ralph Quote
stuart Posted February 2 Report Posted February 2 On 1/31/2026 at 5:21 PM, rcreweread said: I've got some original 10 13/16ths" diameter discs which I've had refaced which I will be taking to Stoneleigh - £17.50 each. I've also got some new standard discs which are £22.50 each Let me know if of interest I'll be on Stand 330C in Hall 2A Cheers Rich C-R They are for later cars Rich, late TR4/4A/5/6 Early cars have bigger discs. Stuart. Quote
stuart Posted February 2 Report Posted February 2 1 hour ago, Ralph Whitaker said: Been looking in original workshop manual and there is no reference to the original thickness of the discs, only reference to no more than 0.060" to be removed if they are being "trued up". I am assuming that they were originally 1/2 inch (12.7mm) and your 13.07 measurement was either a build up of rust or a slight discrepancy in the measurement. So 60 thou being 1.5mm, anything over 11.2mm should be OK including the replacement discs you already have. Remember too that the TR3 was one of the first cars to have disc brakes and the discs were quite thick compared to later cars, for example the discs fitted on my Dolomite are only about 10mm thick from new in a car of similar weight with servo assistance, even the Sprint uses the same discs as my lowly 1300. FWIW I have skimmed discs fitted on my 3a. Your rear brakes do not even look bedded in yet, the pic of the offside shoe shows the only contact seems to be the last couple if inches before the adjuster. It might be worth checking the backplate as it is common for the handbrake lever to wear a notch in the back plate which prevents the cylinder sliding back and forth as it must to obtain proper braking on both shoes, though this normally means that the trailing shoe does little work and the shoe directly operated on by the piston in the cylinder does most. If the backplate is grooved then it needs welding up and grinding flat again. Ralph You can find the minimum disc thickness marked on the edge of the disc. Stuart. Quote
james christie Posted February 2 Report Posted February 2 Wonderful source of information this forum. I've been looking at the (original) discs on my 3A for 52 years now and never knew that! james Quote
iain Posted February 2 Report Posted February 2 (edited) Agree these shoes look very good. I’m not sure the 10” shoes have steady posts? I remember chatting to Neil R about this years ago and coming to the conclusion that they don’t? Iain Edited February 2 by iain Quote
rcreweread Posted February 2 Report Posted February 2 2 hours ago, stuart said: You can find the minimum disc thickness marked on the edge of the disc. Stuart. Not when it's rusted off! Cheers Rich 3 hours ago, stuart said: They are for later cars Rich, late TR4/4A/5/6 Early cars have bigger discs. Stuart. Stuart - Understood but I thought the later TR3As also used the smaller discs, but I bow to your knowledge! Cheers Rich Quote
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