• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

Brake Pads - question

Share this page

JPSmit

JPSmit

Moderator
Staff member
Silver
Country flag
Offline
So, was watching Wheeler Dealers the other day and they were repairing a Volvo 544. braking power was an issue and Mike Brewer wanted Edd to do a disc brake conversion. Instead he put uprated pads on the drum brakes. IIRC standard pads have a braking coefficient of <2 (whatever 2 is - unicorns or something) the pads he put on had a braking coefficient of 4 - so, about 2 1/2 times the braking power. Interestingly he demonstrated this by dragging the pads across the work bench and the one was harder to slide.

Of course I have no idea of the brand, but, does this ring a bell for anyone? Are these pads readily available? Are they customizable?

According to the show Mike didn't realize they weren't discs when he hit the brakes on the final drive.

Yes, I know it is TV, but, it seems like this could be a good and cheaper alternative to a disc brake swap for early car owners and, in my case, the Austin 7 is apparently notoriously under braked.

does this ring a bell for anyone?
 
I think you've got at least two different questions. Friction, and brake type (drum or disc).

Increased pad friction will give you a faster stop with the same brake pedal force. But increased friction also leads to increased heat build up. If you're talking pads on a disc system, the disc system dissipates heat better than drum brakes.

More to the point (!), if you're talking about your Austin 7, I assume it's got drum brakes, not disc brakes. So if you use higher coefficient (higher friction) shoes, you build up more heat due to increased friction. You stop faster with the same pedal force, but you're more likely to experience brake fade.

http://knowhow.napaonline.com/disc-vs-drum-brakes-pros-and-cons/

The bells are ringing ... Ding Ding!
 
My drum brakes have ceramic shoes which stop as good as discs. Continual stopping can bring heat but pads can take it drums would be turned or replaced more often. Plus side of drums, no drag as discs, gas saver. Stopping power same, just heat issue. Use a drum that throws heat and ceramic pads. Drum brakes if setup properly last a lot longer than disc pads. I have 4 cars with shoes, 2 MK1 Jags, 64 Valiant, 98 Ford E350 V10 RV with shoes in rear.
 
Ted Schumacher can reline your shoes with a "Kevlar" material that works very well on the street IMO.
http://www.tsimportedautomotive.com/tr3_tr4a.html

Unlike many "racing" compounds, the stuff Ted uses works very well cold as well as hot. It has a good coefficient of friction and excellent fade resistance. It also seems to be gentle on discs and drums (some friction materials cause rapid wear). It seems to wear well, IMO, not as good as some perhaps but much better than others; and I would rate dust generation as moderate.

Another trick with drum brakes that seems to be something of a lost art these days : After relining (or even when new), it helps to have the shoes 'arced' to match the drum surface. There is a fairly simple machine that grinds the friction surface to exactly match the measured diameter of the drums. It also roughens the surface, for best friction.

As noted, the big benefit of disc brakes is cooling/lack of fade. Until they overheat, drum brakes should give you all the stopping power you can use. That's not to say the brakes on an Austin 7 aren't poorly designed though; I have no experience with a 7.
 
TR3driver said:
That's not to say the brakes on an Austin 7 aren't poorly designed though; I have no experience with a 7.
Click to expand...

thanks for the info - and actually they are poorly designed - partly because prewar but they also have pressed steel drums.
 
I understand that the Austin 7 doesn't have very good brakes. But go ahead with "gripper" shoes. I don't think it will go fast enough for brake fade to be a major problem. :wink-new: Much like my Prefect in that regard.
 
J-P, you can get soft linings for your A7 brakes, most savvy owners recommend them. Your pressed drums are o.k., the main issue with A7s is the means of operation. For example, the front brake cables pull at the bottom of the backplates. The brakes come on, the axle twists forward, the cables slacken and the brakes come off.
You'll get tons of good advice on Austisevenfriends.
 
pdplot said:
A soft pad will probably wear faster. Not a problem on your Austin 7.
Click to expand...

No doubt I could probably stick my foot out! :smile: and yes Roger have discovered austinsevenfriends. Almost got to meet one in Guernsey a couple weeks ago but we connected too late
 
The numbers the show referenced are coefficient of friction - called mu.

The coefficient of friction (COF) is a number that determines the amount of friction between materials in contact. It is often designated by the Greek letter mu (ÎĽ)
 
Koop said:
The numbers the show referenced are coefficient of friction - called mu.

The coefficient of friction (COF) is a number that determines the amount of friction between materials in contact. It is often designated by the Greek letter mu (ÎĽ)
Click to expand...

helpful - thanks
 
Back
Top