Wiring calliper bolts

[richardhinds]

I'm interested in the general opinion of members:

Is Locktite on the calliper bolts sufficient to secure them, or should they always be wired?

I ask because all the cars I've ever worked on have used Locktite ( or equivalent ) on the calliper bolts, apart from my 1965 S type, which has the two calliper bolts wired together for safety. Has the introduction of modern fixatives like Locktite rendered the old practices redundant?

I'm struggling to make the "wiring" of my calliper bolts look neat and tidy, and wonder if the technique of "wiring" is still necessary.

I'd be interested in members opinions.

Regards, Richard

[davidr]

The thing is, the MOT inspector can't see loctite but he can see missing lock wire

[B87UL]

Richard

One problem is that once you allow untrained hands to make automotive safety decisions you are heading for a disaster. I have seen horrendous issues when Loctite has been used and has not been cleared out before another application. If you use Loctite I presume you have full sets of taps and dies to clear out the old material before you are caught with a “bottoming” bolt giving false readings of its tightening torque?

I appreciate the power of Loctite and its abilities, and I have used the product since about 1962 in many countries and climates. However, as on aircraft, wired fasteners generally provides instant recognition that the fastener has been tightened and locked.

The design in question, as it does also on the rear brakes, requires the retaining set screws to be wired. It is true that later designs, by nature, should improve the breed but for peace of mind, for a few pence, wire all the drilled set screws.

Although it may be old fashioned, wiring certain fasteners like drain plugs and carburetter banjo bolts also provides extra visual reassurance.

For about £10 you can buy a set of lock wire pliers on internet that will provide that professional look on wired “automotive” applications. These pliers will be limited to right hand twisting of the wire, unless you pay considerably more for aviation wired pliers that will provide right and left twist. You can operate the automotive pliers manually to provide a left handed twist.

[richardhinds]

Thank you for your considered replies. I will be wiring the caliper bolts.

Now for a new query! What is the best way to loosen slightly corroded brake nipples?

I've been applying penetrating oil around the nipples for a few days now. I have some "nipple spanner's" ( an 11mm will just fit) but I'm frightened to apply too much torque and risk sheering the nipple. Equally, I'm wary of applying much heat in case that damages the seals on the caliper pistons. Is a caliper re- build beckoning?

As usual any advice/ tips gratefully received.

Richard

[davidr]

Hi Richard - I find Plus Gas to be the best releasing fluid and patience to be the best tool. A six sided socket or ring spanner is the best way to avoid rounding off the hex.
I take a long term approach to these things - my method is to put a small squirt of Plus Gas on every time I go past and let time do its work. Patience usually works!
good luck!

[B87UL]

Richard

The moderator has provided some good advice, including the use of plus gas that I favour.

A couple of points that may prove helpful. Try gingerly tightening the screws a little once only before endeavouring to undo the screws. Don’t try continually tightening and untightening, as reversals are apt to shear bleed screws.

After a few applications of plus gas you will find freezing the bleed screw immediately before extraction may be to advantage. Freezing spray can be sourced from plumbers’ merchants and can be just as helpful as heating with a little less danger.

Some additional advice. If bleeder screws are partially seized before extraction, always renew them. Long extendable ones are available if required, that provide easier access to the hexagon.

[BookerME]

I had exactly the same problem on my 420.

I was lent a set of Flared Spanners which are the proper tool for the job. Sometimes they’re called a Brake Spanner and sometimes a Crow’s Foot spanner. They are like a ring spanner with slot at the end that allows you to fit it over the pipe.

Mac

[Martec]

May I add to this post, when I first built our MkII and put it on the road in 2000 I used Locktite on the caliper bolts. A little later on the M6 I got a god awful row when applying the brakes, I managed to stop on an up hill off ramp and found that one caliper bolt had disappeared and the other was bent, the caliper had moved and was hitting the inner part of the disc and hub, the handbrake pads had also disappeared.
With a rock behind one wheel I replaced the two caliper bolts from stock carried in the car. Later in the car park of 'David Manners' store I fitted new handbrake caliper pads and checked all the caliper bolts, all were slack!

At home I contacted a local specialist bolt supplier who advised sticking with standard Mild Steel bolts, I then drilled the heads and used SS wire to secure them . No further problems ......... on that score.
Brian