New Brake Lining

[Dave Russell]

I recently replaced the generic brake linings on my BN2 with Porterfield R4S compound.

This is a street version of their carbon/Kevlar R4 compound. Recommended for moderate to severe street use. The linings were both bonded & riveted.
https://www.porterfield-brakes.com/porterfieldckshoes.html

The result was nothing short of amazing. For the first time - I am able to lock the wheels at speed, if I wish, no pulling or grabbing, just very quick stops. Pedal pressure is noticeably less. No signs of fade after 10 successively harder stops from high speed to break in the shoes a bit. Lot of stink though. No noise or squeal as is sometimes the case with hi performance linings.

I always thought that the BN2 with it's 2 1/4" by 11" drums "should" stop very well with a car this light. It finally does. The brakes stop well the first time from cold, no warm up required.

The factory drums were supposedly surface hardened to reduce wear & they didn't recommend regrinding them. At 85,000 miles the drums are still round & show no wear. I just lightly sanded the inner drum surfaces with 220 grit. Porterfield arced the shoes to my exact drum diameter, 11.005".

Not cheap at $50 per wheel including shipping but well worth it to me for the greatly improved performance.
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[aeronca65t]

Maybe I'll try that on my race Sprite.
I've been thinking of changing to rear disk (probably using Miata rear calipers), but this would be much easier.
Thanks for the tip....I'll look into it.

 

[JamesWilson]

Porterfield is really popular with the nasty boys:

https://groups.yahoo.com/group/modifiedhealeys/

A search will turn up numerous positive comments....

 

[Johnny]

Thanks for the tip Dave. Did you have to replace the metal portion of the brake shoes? My BJ7 original rear brake shoes look worn where the wheel cylinder contacts the shoe. Also, where's a good place to buy new hardware, springs etc.

 

[Dave Russell]

Hi Johnny,
No, I didn't replace the shoes. A little wear in the contact areas is ok as long as there are no rough/sharp corners. I have always had good luck with British Car Specialists for parts. I rebuilt the hydraulics a couple of years ago, so just replaced the shoes at this time.
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[tommyp]

I put Porterfield shoes on my BN2 and had to grind some from the pivit end to let them go on the front ones made noise so i went back to my old ones that had good pads it work great now no noise hard pedal

 

[Dave Russell]

Normally, Porterfield does not have used BN2 brake shoes available & you have to send your's to them for relining.

One slightly odd thing about the BN2 brakes is that they require less than the normal lining thickness. The book specs something like .175" lining thickness. If the linings are much thicker, the drums won't go on.

I specified lining no thicker than .190" & radius ground (arced) to my 11.005" drum diameters. This assured full shoe contact with the drums & that the drums would actually go on over the shoes.

If the linings are not arced to the actual drum diameters, there will be only partial drum contact. Grinding the shoe abutments to correct for wrong shoe radius or lining thickness may allow the drums to go on, but is not optimum.

If this is the case, the linings will eventually wear in to match the drum radius & achieve full contact. It would just take a lot of time to achieve full shoe to drum contact & stopping power. There could also be noise & vibration during this wearing in process.

The shoe steady post heights should be adjusted per the book to square the shoes to the drums. If not correctly done, again, only partial shoe to drum contact will result. A dab of green Girling grease should be applied to the steady post felt collars & to the ends of the shoes where they contact the wheel cylinders & abutments.

Drum brakes have to be perfectly set up to achieve optimum noise free stopping. Discs are much more forgiving.
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