Rear Brake Adjustment -

[gonzo]

Last weekend I drove the Austin Healey from San Francisco -Bay Area to Santa Barbara and back again for a total of about 10 hrs of drive time. It was a beautiful drive on HWY 101 with weather along the coast as expected for this time of year – cloudy and cold – “June Gloom”. Since the car smoothes-out at about 70mph, I usually drive at that speed returning an averaged of 22 mpg.

Lots of weird bugs and crud on the car, so its time to clean/wax and maintain the car.

Inspecting and adjusting rear brakes on the BJ-7 today and have questions on proper adjustment and some observations to share.

On brake adjustment:
While rotating drum, turn adjuster in one click-at-a-time until it drum locks, then turn adjuster out one-click-at-a-time until drum turns free. There’s usually some drag or rubbing after this adjustment. Is this acceptable or should the drums rotate completely free with no contact with brake shoes?

On hub / spline install:
The five nuts that secure the rear hub/spline will snug down to their recesses, like lug nut, but their flats are almost flush making it difficult to get a socket on them. Is this correct? Shouldn’t their design be more “lug” than “nut”? I missed the forum and sorry that I haven't posted in a while. GONZO

 

[Dave Russell]

Hi Mitch,
It HAS been a while. This usually indicates that things are either going well, or so bad you don't want to talk about it.

A light rub is ok on cold drums. As the drums expand from heat during use, they will rub less.

The lug nuts should not be sunk so deep that there isn't room to get a good grip on them. Possibilities are: the countersinks on the hubs are worn too large. The tapers on the lug nuts are worn. The wrong lug nuts are installed.

This is not a place to compromise or experiment. The nuts must be torqued to 55 ft lbs & be of the self locking type & or Loctited. If one gets loose the rest will follow & a rear wheel comes off. I would try new, correct, self locking nuts. Actually, factory recommendations are to use these nuts only once. If the countersink holes in the hubs appear to be worn, (the new nuts sinking beyond the tapered shoulder) I would replace the hubs.
D

 

[gonzo]

Dave-

Thanks for your helpful and thoughtful response. Things are going very well, thanks. Work has taken priority but I'm taking every opportunity to play with the Healey.

The nuts are of the self locking type; of correct size and thread for the hub/spline studs (have originals for comparison) and were renewed during restoration 10+yrs ago. However; I have to admit these nuts have been removed and installed numerous times. It's very possible that over time the hub/spline holes have enlarged - something I haven't considered - as you suggested. I'm prepared to purchase new rear hubs and replace all 10 locking nuts as an added precaution. Do you have a particular source to recommend or shall I purchase from the usual suspects?

Wow - Reason #1 not to miss this forum.

Thanks again, GONZO.

 

[Wana]

GONZO, I just bought some from Victoria British (hub nuts). They look correct, as compared with the ones I removed. They don't appear to be self-locking, however. I will be using Loctite with them.

 

[Dave Russell]

Gonzo, Wana,
I have attached a pic of the correct lug nut. Note the slits just below the top threads. The top threads are actually deformed to make them bind. This particular example is worn beyond use. As I said above, make sure they are tightened to 55 ft lb & check once in a while. If they loosen even a bit, it's a short time until you are screwed!

I have gotten the correct nuts from British Car Specialists in Stockton, CA.

 

[Wana]

Dave - thanks for the info and photo. There's an old saying, you don't know what you don't know. Upon closer inspection, the ones I got from VB do have the slots like the one you showed. See attachment.

 

[Wana]

Oh, I was going to ask - does this mean that I should not use Loctite when I put the new nuts on?

 

[tahoe healey]

Hey, Gonzo. Going to Yosemite this next weekend?

 

[Dave Russell]

[ QUOTE ]
Oh, I was going to ask - does this mean that I should not use Loctite when I put the new nuts on?

[/ QUOTE ]
You should not need Loctite the first time with new nuts, but I would use blue or green Loctite for a little extra insurance.
D

 

[gonzo]

Hi Ya TH!

I've been too many places in the past two weeks that I'm holding-up at home and doing some repairs on the Healey. Yosemite sound like fun, but it'll have to wait. Thanks for asking though. Enjoy the event and take lots of pics! I hear the falls are amazing right now.

Dave-
Thanks for the pic and further instruction. The stubby-nut matches the ones installed now, but prior to this hundreds of miles were were on incorrect nuts. This probably accounts for the enlarged recesses. GONZO

 

[Ray Smith]

The left rear drum on my BJ7 appears to have a little drag with the adjuster turned out all of the way. What could cause this? After a short drive, the left drum is warm, not hot. The other drum is cold.

Ray

 

[tahoe healey]

Dave, what are your feelings on the green loctite to save the locking nuts from being used to much now that the nuts are in place?

 

[Dave Russell]

Ray,
The adjustment appears to be dragging a bit. Try backing the left drum adjustment off a notch. The rear adjuster is four sided so one notch would be 90 degrees rotation. I probably don't need to say this, but make sure that the adjuster is not between one of the four sides (on a corner/high spot) which will make the adjustment tighter than it should be. If this fails see next paragraph.

Healey brake shoes are intended to have 3/16" lining thickness or a bit less. If the shoes are relined with anything thicker there may not be sufficient clearance with the adjusters backed out. A brake shop can regrind the linings to the correct thickness. They need to have a drum to measure to set the exact contour.

Almost all drums are slightly out of round which causes slight variation of shoe drag as the drum is rotated. The friction surface of original drums was reportedly hardened. My BN2 drums show no wear with about 85,000 miles. Regrinding the drums, as is often done, will remove the hardened surface & the remaining drum may wear faster. I personally, would not regrind these drums.

TH,
Loctite won't save the locking threads. There is still a metal to metal lock on an unworn nut which will wear some each time the nut is removed. It certainly won't hurt anything to use some green Loctite & will give some added insurance. The best insurance is to periodically check for 55 ft lb torque on the nuts.

D