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MG MGB Technical - MGB front brake upgrade - which option ?

Later this month I'm following Top Gear's advice and driving up and down the Stelvio Pass with some other like-minded nutters on a boys week out (yippee!). Unfortunately, Stelvio is apparently known for frying brakes- eek!

Since I only have the standard pads and disks I am of the opinion that I may end up re-creating that final episode from the Italian job..last year, a trip to Chamonix provided a bit too much and things stopped working part way down...

What are the options available? Would fast road pads be ok (mintex 1144. greenstuff etc.?) or is a 4 pot caliper and vented disks the way to go? I have heard that peugeot 505 turbo vented disks are a cheap option and fit? likewise Rover SDi 4-pot calipers also do the job - anyone done this? I guess I could go for the Hoyle conversion but pricy?

Finally, do the cross-drilled disks make much of an improvement?

Any help greatfully appreciated.

yours, Charlie Croaker...
S Camsell

I paticularly like the kits with the alloy hubs. As well as better brakes, you get alot less unsprung weight. Two for one.

http://rebornco.com/bigbrake.htm
these arn't the only suppliers hunt around Search MGB big brake kit
peter

By no means an expert but my 2 pence worth, I wanted to change my brakes last year, after a bit of reading, the common advice seemed to be for fast road use, the standard calipers and discs with greenstuff pads are fine. I found a kit which had greenstuff pads, drilled and slotted discs, new original spec calipers and braided hoses. Fitted it all and the brakes are great, I have never managed to get them to fade significantly but I have never given them the kind of abuse you would be expecting to give them on "the pass".

two things I found:

1) brakes squealed like mad. Eventually it was cured by chamfering the edges off the pads on the leading edge. This worked a treat.

2) the amount of brake dust on my wheels is nothing compared to what it used to be like! if you have wires greenstuff pads are a great upgrade!!!

I dont think the drilled and slotted discs really add anything to the braking performance but they look smart!

http://www.runboard.com/baberdeenmgownersclubforum.f1.t125%7Coffset=10

If needed I will look out my reciepts to find the cost and supplier of the brake kit.

Regards

Chris
C Briggs

Greenstuff or Ceramic pads on a stock system (assuming it's in good order) should be more than adequate for any road use. Of course proper downshifting and holding some speed through the turns will make life much easier on the brakes and your right leg. ;)
Steve Simmons

Interesting what Chris says about dust and Greenstuff pads. On my V8 with full Hoyle kit, including Peugeot ventilated discs and 4-pot calipers, the Greenstuff pads produce huge amounts of dust that spoil my alloy wheels after only a few dozen miles.

Incidentally, the Peugeot discs need to be re-drilled to fit the MGB hub, a job best left to an expert I think. I bought mine from John Hoyle.
Mike Howlett

Heat is the problem.

Removing the dust shield from behind the disc will increase the air circulation helping to cool the disc as will ducting air from an air dam.

If you are using normal brake fluid make sure it is fresh. A major cause of fade it water absorbed by the brake fluid vapourising due to the heat.

Different pads may be more resistant to heat but larger calipers will not help much. In fact for a given size of disc they could reduce the loss of heat to the air as a higher portion of the disc is covered.

Drilled, slotted of vented discs will disipate more heat to the air due to their larger surface area so less should go into the rest of the system.
David Witham

Thanks folks,
Really usefull stuff here.

Action plan:
1) fit some greenstuff pads
2) re-new brake fluid
3) fit a servo!
4) improve my leg muscles...

Mike - what kind of difference did you experience with the Hoyle kit? Was there an improvement to ride/handling as well as braking? I've already got the Hoyle front suspension which is in a different league to the old B setup.

MGJohn

Sorry forgot to log-in - comment below was from me!

Thanks folks,
Really usefull stuff here.

Action plan:
1) fit some greenstuff pads
2) re-new brake fluid
3) fit a servo!
4) improve my leg muscles...

Mike - what kind of difference did you experience with the Hoyle kit? Was there an improvement to ride/handling as well as braking? I've already got the Hoyle front suspension which is in a different league to the old B setup.

Simon
S Camsell

Also, for the record mine, is an NG TC V8, hope this is still allowed on this site! Just thought you guys were the most informed on all things B-related1

Cheers!

Simon
S Camsell

A word about cross drilled brake rotors. Check them much more often than standard rotors, they tend to develop stress cracks radiating out from the holes after a while which could eventually cause a rotor failure. Dimpled or slotted rotors don't seem to have the same problem. I had a set of drilled rotors on my midget for several years, but last year I pulled them off and looked closely at them and did find small cracks starting around seveal of the holes. I replace them with standard Brembo rotors.
Bill Young

Everyone seems to have it about right.

The only upgrade needed for spirited street (or race) use is appropriate pads.

I do not like crossdrilled discs as the risk of cracking is not offset by any nominal benefit. grooved discs OTOH can be useful but really aren't needed on the street.

Anyone that puts on 4 pot ventilated brake packages on an MGB is:

1 - a show off more interested in having people admire his car than in real performance, or

2 - drives at highly illegal speeds and needs locking up ;-)
Bill Spohn

3. is concerned with people cutting them off in such a small car and wanting to upgrade their brakes to a more modern capacity for saftey.

4. Taking an off ramp faster by using the brakes at a later point than normal
James

Hi,

I fitted cross drilled and grooved (Lucas i think) discs and greenstuff pads to my supercharged BGT and to be honest didn't rate them any more than standard ones and they did create alot of dust,
To this end i have just purchased a set of Frontline alloy four pots and vented discs, but am still in the fitting stage. The beauty with Frontline is they can squeeze them into 14" wheels.
Seems to me alot of people like to make their cars go quicker, but often don't like spending money to slow them down!! Your brakes can never be too good??

Ian Jackson
Ian Jackson

OK guys, I admit it, the Hoyle 4-pot calipers don't feel much different from the standard brakes in normal driving, but I guess they would last a lot longer under duress. Not that I've tried, yet.

Simon, I don't mind your NG TC V8. My own GT V8 conversion is so modified from a standard car that it is almost a different vehicle. If you think the Hoyle front suspension is good, you should try the rear independent set up. Its truly excellent, if expensive. No more hopping over bumps. No more spring wind up. No more lateral axle movement. Less than half the standard unsprung weight. And rear disc brakes too. The adjustable Gaz dampers allow you to keep the rear springing soft and compliant and the car just feels glued to the road. I'm using a standard chrome bumper ride height and about 1 degree negative camber.
Mike Howlett

James, stock brakes are more than capable of locking up all four tires. More powerful brakes will not stop you any faster, they will just lock the wheels quicker. The only advantage to aftermarket brakes might be improved modulation, but for normal driving it isn't needed. Consider the fact that most racers use the stock setup, as did the Works factory cars.
Steve Simmons

"Consider the fact that most racers use the stock setup, as did the Works factory cars."

Would that not depend of the rules of the Race if non stock items are permitted?

I have the Zeus 4 pot caliper (takes the same pad as a DB5 or a E Type) these work really well far better than the standard set up, also on the rear I use a vented drums.

When the car is pushed hard I got no hint of brake fade, should also say the choose of Tyres also make a big difference to stopping!!


K Harris

I use AP racing radial four pots calipers, with AP vented rotor, and inevitably 15" wheels
pedal box is unlike too


toto tata

I use an infamous neakname because:
Your access code has been banned from this service.
This is normally because it has been published on the Internet and is now insecure.?????
Sorry.

pedals box



toto tata

Just fyi, full-spec 'cross-drilled' discs, such as those used in Porsches, have the holes cast as part of the production process, not drilled afterwards.

SS7
MGJohn

Steve Simmons said it perfectly. The stock brakes in good shape are more than adequate. I vintage race a '62 MGB that dynoes at 138HP to the rear wheels. The only changes are a later (still MGB) dual circuit master, braided steel flex lines, and Porterfield Racing pads. My '71 BGT street car uses braided steel lines and Greenstuf pads. Never a problem!

Paul K

This thread was discussed between 02/06/2009 and 11/06/2009

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