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MG MGB GT V8 Factory Originals Technical - V-8 brakes
|I found two TR 2000's in a wrecking yard and made a deal for the front calipers. I wanted to use the inner sections for BV-8 brakes. Well, just before the they were removed I looked at the casting numbers and the dimensions. Lo and behold, they were exactly the same as standard MGB items. What gives? I've read in numerous books/postings that TR 2000/2500 inner caliper halves when mated to MGB outers allow the thicker MGB GT V8 rotors to be used. Am I missing something? The inner sections did not have sufficient room for the V-8 rotors.|
I can't explain that the dimensions were exactly the same as MGB but you are entirely correct. If the MG/Triumph caliper halves are mated the 1/2" MGV8 disc rotor should fit. I have done this myself.
Some Triumphs had Girling brakes and some Lockheed. Only the Lockheed bolts line up.
|Ian G Buckley|
Thanks for the reply. Did the TR 2000 use 1/2" thick rotors? The ones that I looked at had approximately 1/3" discs as per a 4 cyl MGB.
The thread you need is V -8 calipers, dated 4/8/02. There is plenty at that thread in the archives. Another is V8 brakes dated 30/7/00 and this says the standard rotor is 8.7 mm (about 1/3") and factory V8 is 12mm. I don't know what the TR 2000 had, sorry. The car I took my halves from was a Triumph 2500 saloon.
|Ian G Buckley|
|The MG/Triumph brake trick is with the 2000 and 2500 saloon cars front calipers, not the TR.|
|Thanks for your replies. Roger, the cars I was looking at were 2000 saloons. I wrote TR because I was being lazy. The 2000's calipers appeared to be identical to an MGB piece I carried with me. I must be overlooking something. Any thoughts?|
The calipers will be identical except that the disk/rotor runout is more than the MBG disk/rotor runout. The brakes are commonly found on the early 70's triumph 2000. All the other models I have looked at have a girling caliper that looks nothing like the MGB equivalent. The inner 1/2 (actually 3/4) where the disk runs is about 16mm rather than the MGB 11 mm. The caliper is a lockheed as well.
Hope this helps!
|Allan, Roger, and Ian,|
Thanks for the replies. I understand that the inner section of the Triumph caliper must be mated to the outer section of the MGB caliper to achieve the desired results. I must have hit upon some odd-ball 2000's. They both have Lockheed calipers and both sets have the same casting #'s as an MGB caliper on the outer section and the inner section where the rotor lives has the same dimensions as an MGB item and appears identical. The rotors are the same thickness as an MGB rotor that has been machined. I looked very closely and took measurements. I suppose that, as was typical with British cars of that era, parts were used as they were discovered in the bins. Now, does anyone know where I maight find a decent pair of proper Triumph calipers even a pair of 4-pots from a Princess? Thanks again for the help and happy holidays!
|Does anyone know if the front calipers from a Jag XJ6 will fit the B spindle? I saw a set in the junk yard recently and they appeared to use the thicker solid rotor as well as have dual outer cylinders which make the overall width less allowing a little more wheel clearance.|
I used a pair of std Triumph 2500 calipers with V8 discs when I upgraded my 1800 brakes. If you use V8 wheels or alloys with a similar clearance, you don't need to split. Leave them as they are (but fit new pistons & seals).
The 'correct' Triumph calipers have a large single vertical rib on the outer half which makes them too tight a fit with Rostyles.
|OK. I think I know where I screwed up. I have discovered that Mk I 2000's had 8.7mm(.343 in) wide rotors a la MGB and Mk II's had 12.7 mm(.5 in) wide rotors which leads me to the, ahem, assumption that the Mk I's also used different, re. narrower, calipers. The cars I found were, indeed, mid 60's Mk I's. That might explain my dilemma.|
|(OK. I think I know where I screwed up. I have discovered that Mk I 2000's had 8.7mm(.343 in) wide rotors a la MGB and Mk II's had 12.7 mm(.5 in) wide rotors which leads me to the, ahem, assumption that the Mk I's also used different, re. narrower, calipers. The cars I found were, indeed, mid 60's Mk I's. That might explain my dilemma.) |
Thanks to everyone for the help. I am always grateful to those who are so kind to contribute to this forum. Allan, your comment that the brakes are commonly found on the early 70's Triumph 2000 made me look at an old parts listing that I have, and, Dave in Yorkshire, thanks for your comments as well. I am running 15" knock-off alloys so I may have no clearance problems any way.
I have no idea whether the Girling brakes will fit but imagine that they will as Dave points out. However, if you want to keep the lockheed look you will ned to get lockheed brakes from a MK2 triumph 2000. In OZ, I have yet to find a Mk2 Triumph 2500 with anything but girlings and the caliper is a true 50/50 spilt caliper that will not mate with an MGB caliper. It may bolt up on it's own. I have scoured the wreckers(breakers) for these brakes and they have allways come off a 72,3,4 T2000. I have a pair for myself and sent a pair to Greg Fast in the US who ocassionally posts as well.
If you get desperate in your search let me know and I will try to locate another pair.
Email if your interested.
|OK, I've got to ask (out of ignorance). I've not broken apart a MGB caliper, but it seems to me that all that is being done is accomodating a thicker rotor - about 3/16 inch if the above posts are correct. Why can't a spacer be put between the caliper halves, o-rings both sides, and longer, quality fasteners? Then a 3/32 inch shim where the caliper mounts to keep it centered. Seems too easy to me - what am I missing?|
|First, hiya Allan, good to hear from you again. The Caliper sections are rebuilt and mated to MGB outers, will be adding them to the car when the front end I'm working on is complete (extended kingpins using MGA lower trunions and dropped spindles to get lower ride height with decent lower control arm angles, all Vintage Legal on the west coast.) Thanks again for the assist.|
Wayne, the reason you can't split 'B' calipers is that they are not split symetrically. The inner 'half' is really about 70% of the caliper width, the outer 30%. The relief for the disk is totally contained in the inner section. The rotor clearance gap was about .48" (scaled off a 'B' caliper), inadequate to even load onto an MGBGT-V8 1/2" rotor, let alone running clearance. The rotor clearance gap in the Triumph inner scales about 0.70", so clearing the rotor should be a breeze.
Since it's cold and dark outside, the rest is from memory. My MGC uses Girling calipers, and they are split in the rotor clearance gap. A spacer plate will work in this application (but they already run a otor about .50" thick- good if you want to go to a vented rotor.) The Girling used on the MGC has a hole pitch pattern about .25-.50" larger- IIRC- than the MGB. I do remember it's not the same.
|"The relief for the disk is totally contained in the inner section. "|
After reading this, I should have added 'and trapped'. That is, the rotor clearance relief is not imbedded on the surface of the inner caliper section, it is totally contained within the section, with part of the casting forming the outside edge of the rotor clearance relief. To fit a larger caliper would require milling a larger slot fore the clearance relief. As the slot would weaken the caliper, I cannot recommend this, and am only stating the technique to clarify the configuration of the caliper
|It's a shame that MGC calipers won't work. I have a pair collecting dust in the shop along with the rest of the bits from a '69 roadster I sadly had to cut up a few years back|
|Thanks, Greg. It never occurred to me that the caliper wasn't symetrical. Darn!|
Would you happen to have the heater control valve (part# 27H 8836) according to the body part list? I have a 69 C GT and am in desparate need of one.
69 MGC GT
74 RWA midget
This thread was discussed between 22/12/2002 and 31/12/2002
This thread is from the archive. The Live MG MGB GT V8 Factory Originals Technical BBS is active now.