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MG MGB GT V8 Factory Originals Technical - Four Pot calipers

Are there any aftermarket calipers the same spec/or for vented discs,that are the same as Austin Princess?
Everyone seems to want these calipers for all sorts of modified cars,its a wonder they are not available,is someone missing a market opportunity? Willwood/HiSpec Etc are you listening!!!
Dave...
Dave Lowe

Dave,
http://www.apracing.com/roadcar/caliper/data.asp?family=CP5100
Cheers
Erik
Erik Kallstrom

Dave,

What spec do you want

http://www.cambridgemotorsport.com/product_templates/product_default.cfm?menu_temp=brakes.cfm&dep_id=10&prod_id=444&ass_id=180

Paul
Paul

I fitted 4-pot Wilwood (note correct spelling) brakes to my "factory" B GT V8 many years ago. Looking at the photographs I think Cambridge MotorSport may well be offering a Wilwood kit.

I am not sure if I have all the part numbers now, which would enable you to purchase direct from Wilwood; and they may in any event be superceded.

However Wilwood were most helpful when I purchased direct from them, although the calipers they supplied were about 0.05" too large to fit withing the factory V8 wheels in the first instance.

http://www.wilwood.com/

also see their tips:-

http://www.wilwood.com/products/techtiplocator.asp

I use Greenstuff pads on my MGA, BGT V8 and RV8 all from Powerstuff; who are most helpful, and who would be well worth talking too before making a decision. (An aside they used to have excellent prices on alloy radiators.)

PowerStop Brakes Limited
PO Box 129,
Chipping Norton,
Oxfordshire OX7 5GR
Tel: (+44) 01608 646837
Fax: (+44) 01608 649344
sales@powerstop.co.uk

Finally I am sure that you will find that Clive Wheatly would be delighted to help.

NJSS
Nigel Steward

I hate double posts, but I should have added that Godspeed will make a 4 pot kit for ANY car:-

http://www.godspeedbrakes.co.uk/

They also sell reconditioned 4 pot calipers.

NJSS
Nigel Steward

You could also look at the SD1 four pot caliper and the early 1990's ford transt four pot. I haven't checked the part numbers but both appear to be made from the same castings.

Also since you can fit Land Rover Discovery pads in them they are cheaper to use than the princess caliper.

Dave
Dave Brooke

Dave,

If I recollect correctly the princess calipers match piston area of B wheras the SD1 are larger which will reduce efficiency of rear brakes.

Paul
Paul Wiley

Paul,

Yes the piston area is greater but since the caliper will not be used with the original disc setup the charateristics of the system have to be re-evaluated anyway.

Personally I've found the rear brakes to be too efficient because of the increased forward weight transfer when braking hard and have had to fit a limiting valve. YMMV

Dave
Dave Brooke

Yes, SD1 4-pots have 15% greater surface area, so there will be a "gearing" effect. Princess is within 1% of standard MGB.
Comparative piston sizes...Standard MGB = 54mm, Princess 4-pot = 2x 38mm, SD1 4-pot = 2x 41mm, SD1 2-pot = 57mm, Wilwood 4-pot Dynalite II (Part No. 120-1056) = 2x 34.9mm, Wilwood 4-pot Dynalite II (Part No. 120-1052) = 2x 44.5
Pete
Pete Green

Pete,
I measured the pistons in my Volvo calipers tonight, they are like the Princess 4 pot, 38 mm each piston. Just FYI.
Jake

Jake,
What year/model Volvo did your calipers come from and did it use vented or non-vented rotors? I'm mentally trying put all of the bits and pieces together from various posts on this subject before I go to the junk yard. It would be great if someone would do a short outline on using Volvo 4 pots and what exactly is required. A record of the above info as well as dimensions for adapters, rotors, caliper mounting hole mods, etc. would really be beneficial. The archive is fine, but with it's primitive search function, a guy could spend all day looking for a small detail. Thanks.
David
David

Guys,

Although slightly OT you may find the following of use http://brembo.progettointernet.com/Eng/Disco_dimensione_main.htm
in finding a disc.

Dave
Dave Brooke

Volvo four pots are like Princess calipers. Just about same design too. Bolt holes are different though and will need redrilling. Is this a safe thing to do?
The model is the older 240 (or are there more?). Every Volvo dealer has a sheet with the tech details of this car, incl front brake specs. Since Volvo's last forever, they might even have some items you can have a look at.

Transit calipers do not fit the B, as far as I know. The pads however fit to B and GT V8 calipers.

Frank
Frank de Groot

Volvo 4pots from the early 240 series.

http://www.bromsokrenovering.se/fadel/default.asp?category=5

Scroll down to the bottom of the page and look how nicely they turn out after renovation.

Erik
Erik Kallstrom

David,
I am in the middle of making a prototype brake setup with the volvo 240 calipers. Mine came off of an '86 DL but any of the 240 series will work. They do use a dual circuit brake system so you need to adapt the MGB brake hose to two lines into the volvo caliper. Actually, feel free to check my webpage, it has more info on it, http://www.roverv8.com
Jake

Thanks everyone,I started this thread because I had spent ages on the net looking for calipers,when I went to the sites of brake companys and look for mgb calipers I got nothing,also looking for conversions on the net only came up with,princess,SD1(very very heavy!),or one off brackets to mount the calipers,I have not had time to look at all the sites you mention yet but it looks promising!
Dave...
Dave Lowe

Erik,

How did you go about with the bolt holes? The Volvo four pots are not a bolt-on replacement for B calipers.

Frank
Frank de Groot

Frank,
Im working on the caliper brackets this week, yesterday I got the rotor adapter machined up most of the way, so once i mount the rotor to the hub, then put it on the upright, Ill be able to see where I need to put the caliper and how to fix it on. I want to make up an adapter so as to avoid having to drill out the caliper mounting holes. Ill keep a record of my progress on my website in the brakes section.
Jake

Frank,
I have“nt done the Volvo 4pots. I just sent a link for people to see the calipers so many talk about. I am in the process of converting to Princess 4pots. "Short bleeders not fouling 14" rims", remember?

Cheers
Erik
Erik Kallstrom

Speaking of princess calipers...
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=2457092925&category=27377
Jake

Erik, sorry for the mistake.

Jake, I will keep watching your website to keep up-to-date with your progress! Am I correct in that you will probably use custom uprights/mounting points for the caliper? BTW: what is the URL of your website?

Frank
Frank de Groot

Frank,
Youre correct, I plan on making a bracket that will rotate the caliper up higher on the rotor so it will bolt to both the caliper and upright without any interferece or cutting. Should only be another week or so before the completed upright assembly is complete. I have an extra upright, and steel wheel hub so I can make one whole side kind of like a display/prototype model to see if everything will work and fit under a 14" rim. Ill keep the board posted. The web address is http://www.roverv8.com but for some reason its been down for the past two days.
Jake

That will be interesting for Erik as well, because the only real difference between the Volvo 240 caliper and the Princess is the mounting points.

Frank
Frank de Groot

I“ll keep watch!
Erik
Erik Kallstrom

Well, looks like if I want to keep the stock V8 rims, I will have to drill out the holes in the Volvo calipers and bush them to the right size. I will probably just stick them on the mill and plunge down where the center should be for the MGB mounting hole centers with a ball end mill big enough to clean out the other hole, and then use a drill bushing of the right size to adapt it to the MGB caliper bolts. There is just not enough room to put the caliper anywhere else.
Jake

What disc are you going to use with the Volvo caliper? Or am I looking too far forward now?
Have to admit I had some doubts about using custom uprights/adapters. There is very little space inside the 14" wheel.
By the way: piston area of Princess/Volvo caliper and the B caliper work out just abou the same, so travel of brake pedal is not affected.

Frank
Frank de Groot

Yeah, I found that out about the same piston area. I am using a vented Nissan 300zx disc. It is 274 mm diameter, 22 mm thick and 35.5 mm tall. The adapter I made to put it to the hub works great, but the dust shield had to be removed. That allowed the rotor to center in the volvo caliper while it bolts to the upright.
Jake

Well folks I'm getting nowhere!The page on the AP site has mounting centers 130mm and the mgb is 3 1/4 inch.
I emailed wilwood,quote-we do not make anything to bolt up to your mgb.I don't mind making adaptors myself,I have made them from 8mm plate for the granada calipers on my 8inch ford axle,but at least I would like a starting point i.e. a caliper, alloy 4 pot,that is going to fit without rocket science and a cnc mill made adaptor! someone must know the dark secret.
I am using mgc 5 stud hubs by the way!!!
Dave...
Dave Lowe

Dave,

The Wilwood MGC Kit Sold by Rally Design Is 285mm 21mm Kit BK10A at £334 to fit a 15in wheel.

Paul
Paul

http://www.RALDES.CO.UK

Also Frontline are using appox 300mm disc and calipers from Hi Spec on BV8

Paul
Paul

Cheers Paul,I have the Rally Design site on my Favorites but didnll phone them tomorrow.
Dave...
Dave Lowe

Should read-Did not see kit on site,print too small! Will phone tomorrow.
Dave

PS not my fault!
Dave Lowe

I'm using the volvo calipers. I bought a kit thats approved by local engineers.
You need to get the holes re-drilled so that they are a little smaller and a few mm further apart. In order to prevent one of the bolts taking all of the strain, the holes are drilled a little off centre so that you get slightly Vshaped holes, which means that the body of the caliper comes between the two bolts. Take the calipers to a brake shop along with either your MG calipers or an axil stub so they can be sure to get it right. Ask them to recondition and cross drill the hydrolic lines as well so that you may close off one of the hydrolic lines and use just one.
Around here it's done all the time.
Peter

Have ordered MGC kit from Rally Design,Wilwood alloy 4 pot,vented discs,etc,and then it occurred to me! I am using MGC 5 stud hubs on MGB spindles(they fit straight on) and I need to know if the MGC caliper adaptors that will be supplied will fit the MGB spindles?I know the disc works out the same backspace,but has the MGC caliper a different mounting centre or position?
Dave...
Dave Lowe

Dave

If you look at website (not easy to read)
MGC is Lug mounted B is radial - So may need a combination!

Pail
Paul Wiley

Well, today I machined up some lugs from hardened steel .0015" bigger than the caliper holes, chilled them and pressed them in flush. On monday or tuesday I will try and mill the new holes, so I made a spacer to support the ears while they are being milled. Just a progress report, should have them back together next week. New pics on my site.
Jake

Today I milled the holes in the Volvo calipers, the bolt onto the MGB upright like they were made for it. I did take some new photos today, so they should be up on my site later this evening. Looks like this whole thing will even fit inside the stock rostyle wheels without any spacers. Maybe tomorrow will start production of the first setup now that the prototype is finished.
Jake

I'm still building my V8 but I have got Peugeot 505 turbo discs fitted. I have welded 4 pads on the hub disc location diameter and then had them machined back to the disc diameter, If I remember correctle the disc has an inner diameter thats about 3mm too large. The bolt holes have to be slightly modified too. That seemed the best way of doing the vented disc thing for princess 4 pots last year. I got the info from this very site. Happy modifying.
Pete H

Who would be interested in buying a bolt on setup or even parts to complete the setup ie. rotor adapters, dual circuit into single brake lines and T, modified calipers, etc? Just trying to get an idea as to how many people are interested in this kind of thing. Email me and let me know.
Jake

Test
Dave Lowe

Test 2
Is this working?????
Dave Lowe

Paul,drove 120 miles to collect ordered brake kit,misprint in catalogue,21mm vented disc should read 12mm solid,even the mgb caliper adaptor was no good as its for 270mm discs!!!
Dave Lowe

OK, site seems to be working now! when you type out things 3 times and lose them it gets maddddd.....
following on from above,it seems I am going to have to do all of the conversion myself as usual,one point to help me, has anyone had clearance problems of the steering arm/track rod end when using bigger discs?
thanks Dave...
Dave Lowe

Dave,

My original link details were 270x 24mm for B and same at rally design

http://www.cambridgemotorsport.com/product_templates/product_default.cfm?menu_temp=brakes.cfm&dep_id=10&prod_id=444&ass_id=180

The C is stated at 285mm by 21mm by Rally design is this really 12mm solid?

Tim at Frontline is using larger disc on B.

With Midget and larger discs you can space out the steering arm to avoid problem.

Paul
Paul

Dave,

Have you tried Doug Smith as you have a B&C cross, I assume you are using C rear axle and matched front?

http://www.mgmotorsport.co.uk/tuning/mgcr&h.htm

Another point to check is brake balance as C is nose heavy and needed the added torque from larger disc.

Paul
Paul

Thanks yet again Paul! When I ordered the kit from RD I specified vented discs, was told that they did not have the discs in stock, would order a pair in and phone me when ready.I phoned about the MGC hub/MGB spindle combination and told them I would bring it along to try and work something out.
When shown the discs today (12mm solid) I was told the catalogue was printed the wrong way 21mm/12mm.
I was there a long time with the "brake" man and he was trying to sort it out for me but to no avail,Showing me different bits that might be adapted,a friend has the same mgc/mgb combo as me and he used vauxhall calibra turbo discs/princess calipers,but I was trying to avoid getting all the work done to adapt everything,I cant really afford the £800 starting price that some mg shops want for brakes!
I asked on the MGC site and was told about MGmotorsport but have yet to see the spec and prices.

Dave...
Dave Lowe

Dave,

As Doug is mainly C's but does BV8 conversions, so ideal for your cicumstances, another is Dave Vale V8 conversions.

Other options
http://www.kad-uk.com/brake_kit_contents.htm

Frontlines brakes are from here

http://www.hispecmotorsport.co.uk/calipers.htm

Paul
Paul

Well, for anyone following the Volvo/Nissan conversion that I am doing, here is an update. I bolted the modified caliper to the car and fitted both an OE V8 wheel and a rostyle. The caliper clears both, but is closer to the rim on the V8. It rotated around fine but scraped off a bit of corrosion on the alloy center as it rotated around, its that close, but like I said, both fit on their fine, no wheel spacers required.
Jake

Paul,I have emailed hispec to see if they can help,I never thought of Dave Vale,his shop is 500 yds from my house !!!
Dave...
Dave Lowe

Jake,

It's very close and because it is front, you could use spacer to place wheel more to the outside.
Just to make sure. The 300ZX disc you use is 274mm x 35,5 high x 22 mm. Is this correct?
The 604 Ti/505 Turbo has dimension 273x43x20. So spacer for hub-disc is about 8 mm? I also wonder if the slightly thinner disc will be a problem, but I think it is within design parameters. What do you think?

Frank
Frank de Groot

Frank,
My hub adapter is actually more than 10mm, I pushed the rotor over as fas as I could toward the upright. This is what allows the rostyle to fit without wheel spacers.
Those specs on the Nissan rotor are correct.
A thinner rotor (2mm) shouldnt make much of a difference as long as the rotors are centered in the calipers.
Jake

Waited days to get a reply from HiSpec,so went there today,on the website it says the billet 4 kit has alloy bells/separate discs,I didn't notice the little star that states that this is for only kits over 300mm diameter!And if you look on the mgb kit page it does not mention it.So although a very nice helpfull chap at Hi spec, the kit with bells works out at £625 plus whatever extra to machine a set of bells and caliper adaptors to mgc specs!Im back to the £800 pounds again!
After 52 posts I am back at the start doing it all myself!!!
Dave...
Dave Lowe

Here is a new twist to the MGB four pot performance brake setup

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=2463254426&category=33563

http://rebornco.com/bigbrake.htm

Instead of using very expensive brake rotors that still wear out over time, this kit uses rotors from a Honda that cost about $30 at NAPA. The only down side with this kit is it only fits MGB's with 15" or larger wheels.
Evan

Dave, going right back up to near the top, have you checked out http://www.godspeedbrakes.co.uk as Nigel recommended?
Mike
Mike Howlett

Evan,

Re rebornco

I do have concerns when claims like these are made as it is the tyres that stop the car not the brakes.

"Now cars are able to stop in less time and shorter distances than ever before, making original MGB brakes substandard"

Paul

Paul

Oh man, if its the "tyres" then why not just remove the caliper, rotors, brake master cylinder, servo, pedal, wheel cylinders, drums, shoes, emergency brake cable and handle and the brake pipes. that should really lighten things up and make less work for the "tyres" when they have to stop the car.
Jack

Jack

Brembo version

Where can I find test data on stopping distances?
At the speeds that stopping distance is generally measured from (60 to 70mph), the test is primarily testing the tire's grip on the pavement. As delivered from the manufacturer, nearly all vehicles are able to engage the ABS or lock the wheels at these speeds. Therefore, an increase in braking power will do nothing to stop the vehicle in a shorter distance.

Paul
Paul

Warning - be very wary of Hispec motorsport.
Search the archives for the stories - and yes, I do have an axe to grind.
Marc

Marc,

Last time you mentioned probs with Hi Spec did you discuss with RP with regard to resolving any issues?

I have heard of quality probs eslewhere.

Paul
Paul

I have had a look in the archives,but could be on there for days!!! looking for Hi spec. anyone got a clue?
Dave...
Dave Lowe

http://www.hispecmotorsport.co.uk/

Paul
Paul

"As delivered from the manufacturer, nearly all vehicles are able to engage the ABS or lock the wheels at these speeds. Therefore, an increase in braking power will do nothing to stop the vehicle in a shorter distance."



Once.



David
David

David,

Speed and multiple stops are issues re heat, but big front brakes can increase stopping distances.

Paul
Paul

Will someone please tell us all whats wrong with Hispec, I fed up looking in the archives.!!!.
Dave Lowe

I have two different kits which are direct replacement big brake kit for the MGB 11 3/4" rotor with wilwood calipers, and stock cross drill rotors with Wilwood caliper.
e-mail me if interested
Bill Guzman

This has got to be one of the longest threads ever
Peter

Dave

http://www2.mgcars.org.uk/cgi-bin/gen5?runprog=mgbbs&access=&mode=archiveth&subject=36&subjectar=36&thread=2001082513423720923


http://www2.mgcars.org.uk/cgi-bin/gen5?runprog=mgbbs&access=41719411400099&mode=archiveth&subject=36&subjectar=36&thread=2001072720124212259

http://www2.mgcars.org.uk/cgi-bin/gen5?runprog=mgbbs&access=41719411400099&mode=archiveth&subject=36&subjectar=36&thread=200111201836117953
Jim Lema

Jim,THANKS!!!!your a saint.
Dave Lowe

This thread was discussed between 27/01/2004 and 10/03/2004

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