Series IIa Brake Drum Minimum Diameter

[mrmurray]

Does anyone know the minimum acceptable diameter for a '67 SIIa 2.25? I am getting excessive pedal travel. At first I thought this was air in the lines, so I did a thorough bleeding, and still the pedal goes almost to the floor before engaging the brakes. I confirmed that the bleeding was successful by clamping the three rubber lines (I know, bad move) and the pedal was hard as a rock.

I was able to adjust the shoes, but not on all the wheels (some wheels the adjusters kept spinning and the shoe never contacted the drum). Drums look to be original. I am in the process of installing new shoes.

Anyway, I wanted to see if I should buy all new drums, but thought it would make sense to measure the existing drums before dropping the money.

The internal diameter of one drum I measured tonight was 10 3/8 inch across (from wear surface to wear surface). I believe the RN brake tutorial in the technical library states anything over 10 1/16 inch diameter should be replaced.

THANK YOU!
Mike

[ivan]

is she 6 or 4 cylinder engine,shoes and drums are different


ivan

[SafeAirOne]

Yours are at 10.375" diameter. The maximum allowed is 10.060" so yours are .315" too big, and that's a LOT! Can this be right? Did you measure accurately?

Snippet from page 70-2 of the SIII Workshop Manual:

https://farm4.staticflickr.com/3908/14406527261_c11597987d.jpg

[solihull121]

Double check to make sure the brake shoes and springs are set up correctly. Just went through this on my 1971 Series IIA 88" where it took two pumps to get good pedal pressure. Turned out that the last person to work on the truck improperly hooked up the brake springs--connecting the two shoes together which did not let the shoes to move out enough to contact the drum. The correct spring location is to a securing peg. Once that was identified and corrected the brake pedal was fine and firm and brakes worked great.

See this write up and thread for lots of good pictures and info on adjustments that might help:

http://www.series2club.co.uk/forum/forum/index.php?topic=6606.0.

9802

See also TerriAnn's website with similar explanation of this issue:
http://www.expeditionlandrover.info/landRoverFAQ/FAQ_rearbrakes.htm

[mrmurray]

Thank you for the replies. I assumed the springs were incorrect going into this, but sadly they were installed correctly. I measured two of the drums using a calliper. I'll measure the other two when I get the truck turned around. According to these numbers, I should replace the drums. Strange that the one is so large, almost like it is from a different vehicle (military maybe?)


Right Front drum internal diameter = 10.25 (triple checked, multiple locations) (no shoe lock with any setting of adjuster cam)


Right Rear drum internal diameter = 10.0625 (this one I can adjust the shoes to lock)


Any thoughts?
Thanks for the help, as always!
Mike

[tmckeon88]

I'd replace them both (if on the same axle) and have the peace of mind of good brakes. Drums are not too expensive, although nowadays you need to check the diameter on new drums too- I had to have a set of my new ones turned a bit to make them large enough to slide on and off the new shoes. Didn't mind- it meant more solid braking and they would last longer.

Good luck,
Tom