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MG MGB GT V8 Factory Originals Technical - Brake Caliper Parts

I am fitting Princess 4 pots widened to fit over Peugeot 505 vented discs. I now need pins and brake pad retaining spring clips for the wider span. Does anyone know where I can get these in the UK?
P A Hawkins

The RV8 Used widened princess calipers so they should be readly availiable and they can't charge too much just for for pins and clips.


I canít help with the pins or spring clips but where did you get the spacers and bolts to widen the calipers?

Geoff King

8mm spacer kits are available from Rally Design. The kits come with long split pins but not the springs. Also see Ebay item no. 4586683059.

If its of any interest new Princess calipers have become available (or were a couple of weeks ago) from a firm called Flexolite (01684 541941. They are very expensive at £195 and £25 for the right flex hoses (imperial on end, metric the other, plus vat, but at least they are newly manufactured by AP and no worries about refurbishment costs. They also have a single hose fitting so no bothers over external link pipes or internal drilling. They fit straight over MGB GT V8 solid discs (12.5 mm),but will need spacers to accomodate the Peugeot discs.

Incidentally if you want to use the Triumph GT6 caliper bolts to fit these to the hubs there seems to be an error in the Rimmer Bros catalogue. They sent me the imperial sised bolts although described as metric. I got the right ones from Canley Classics in the end and these calipers do bolt straight on to the MGB hubs. I've not tried the spacer kit yet.
Steve Musgrave


Were the caliper bolts from Canley Classics part number 158713: caliper mounting bolt - 16pb metric?

Burton Power appears to have spacer kits for Ford calipers but I couldnít find anything for the Princess (or SD1) on the website.

The Princess 4-Pot caliper spacer kit from Rally Design is part number RD3602. Does anyone know where I could buy a kit for the SD1 4-Pot calipers?

Geoff King

Yes, Geoff, that's the part number and description of the bolts I have. While the threads are standard UNF as per normal mgb and the shanks are the right metric spec. for the Princess capipers, the actual bolt heads are larger than the mgb ones so you need a bigger socket. But they fit ok. They also fit the mgb lock tabs (though it seems the GT6 used spring washers rather than lock tabs).
The Burton Power printed catalogue does have Princess 4 pot spacer kits listed (p.82)as part no RD3272A, at £39.95, though I think you are right they are not listed on the website.
I don't know if a spacer kit for the SD1 4 pot calipers is available, but Rimmer Bros. list new 4 pot calipers for either solid or vented discs.

Steve Musgrave

Hi Geoff as you can see I am still plodding along with my conversion. Working for a living seems to get in the way of these important projects!
How is your V8 performing - looks like you are looking for better brakes!
I got my spacers from a brake specialist in Wales with a very professional looking web site who turned out to be a real sh*t - wrong caliper bolts, a set of pistons that had the chrome flaking before I ever got to fit them and suddenly uncommunicative. He finally agreed to accept them back but reckons they got lost in the post so then I had NO pistons.
A company that was reasonably priced for pistons was "Brakes International" - I will try them for RV8 clips.
With regard to mounting bolts the easiest route is to get sleeves that press into the caliper mounting holes. These were inexpensive and came from Dave Vale at V8 Conversions. Then you use the Standard MGB bolts.
Rover SD1 Calipers
I have a set of twin pots from the donor car - a Vanden Plas. This car already had ventilated discs so the calipers are wide. If you are considering using Rover calipers this is probably your best bet.
I don't reckon its worth having special metric to imperial hoses. I am using Maestro hoses - metric both ends. As I am running new copper brake lines I intend to cut the imperial fitting off, and put a metric on. No problem as long as you have a pipe flaring tool.
Brake Pads
I am also sticking to standard pads - I have heard that "green stuff" is good for track days but not so good for the road where it doesn't get hot enough.
Thanks to the rest of you for your input.
Happy tinkering

P A Hawkins

Hi Pete,

I built my car with four pot SD1 calipers from the beginning and Iíve never had a problem with brake fade but when the time comes to replace the discs Iíll consider vented ones. I rebuilt the calipers with new pistons and seals from Rimmer Bros and Iím using Mintex pads, the discs are standard GTV8.

I bought sleeves for the bolts and metric to imperial hoses from Dave Vale at V8 Conversions, all cheap and easy to fit. There is nothing wrong with using the standard MGB bolts for the caliper but I have seen several requests for a source of the shouldered Triumph bolts and itís nice to know of a supplier.

If your SD1 calipers are surplus to requirements Iíd be interested to purchase them as Iím yet to find a supplier of spacers and bolts etc to convert mine to vented width. Iíll be down south in a few weeks let me know if you want to sell them. They are 4 pot not 2 arenít they? Iím reasonably sure only the SD1 with solid discs had 2 pot calipers.

Geoff King

Hey Geoff
I have a pair of SD1 Vitesse 4-pot calipers for vented discs spare but they need a rebuild. If you want them get in touch on (delete the second K). I am up in Shetland but could get them to you via the airport using airport transfers sevenoaks if needed.

Sorry for hijacking the thread!
Nick Bentley

If it helps any of you guys running or planning to install SD1 ex vitesse 4 pot calipers, I have a set of unused Mintex pads I have no use for: part no. MLB85. Mintex have confirmed that these are correct for the SD1 Vitesse.
Steve Musgrave

Hi Geoff
Yess they are 4 pots
E mail me and I'll dig them out and mail back a picture. I guess you are down in Shepton near Christmas.

I could still do with a part number for the pad retaining clips for the wide princess calipers though if anyone knows it.

P A Hawkins

I am not sure on this but the Rover SD1 4 Pot Vented retaining clips look the same as Land Rover Disco. I seem to recall them fitting mine. As to the Princess I dont know. Not much help.

The brake discussions are always interesting, but at the risk of repeating prevous threads, can anybody tell me why the 2 pot SD1 brakes seem to be a more popular mod, than using the 4 pot SD1. (only refering to use with solid discs). Do you get better feel, similar to original MG brakes if you use the Rover 2pots?

Thanks for your input. I found some SD1 clips from the 4 pot calipers. These are a couple of mm too wide but will fit if I cut them down. So that's what I am going to do.
P A Hawkins

This thread was discussed between 01/11/2005 and 14/11/2005

MG MGB GT V8 Factory Originals Technical index

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