Classic cars forum & vehicle restoration.

[Southernscouse]

Is anyone familiar with the Austin Devon handbrake on the fully hydraulic cars
The brake shoes are good and adjusted but the handbrake is still rubbish
The whole design with its sliding wedge mechanism seems to lack any power to hold the van on any incline

[alastairq]

I ran the question through google, and it came up with the following:-

[alastairq]

post deleted, see below
_________________
Dellow Mk2, 1951 built, reg 1952.
Fiat 126 BIS
Cannon special [1996 registered. Built in 1950's]
----------------------------------------------
Ford Pop chassis, Ashley 1172 bodyshell, in pieces.

[alastairq]

post deleted....trying to get to grips with SQL error messages, sorry
_________________
Dellow Mk2, 1951 built, reg 1952.
Fiat 126 BIS
Cannon special [1996 registered. Built in 1950's]
----------------------------------------------
Ford Pop chassis, Ashley 1172 bodyshell, in pieces.

[alastairq]

Post deleted, see above, sorry
_________________
Dellow Mk2, 1951 built, reg 1952.
Fiat 126 BIS
Cannon special [1996 registered. Built in 1950's]
----------------------------------------------
Ford Pop chassis, Ashley 1172 bodyshell, in pieces.

[alastairq]

[quote] A sticky handbrake linkage is a classic headache on the late-model fully hydraulic Austin Devons. Because the system relies on a hybrid combination of a short front cable, a long chassis rod, a chassis relay lever, an axle cable, and a mechanical axle compensator, there are numerous mechanical pivot points exposed to road grime, moisture, and neglect.
When the system gets "sticky," the handbrake lever may feel tight to pull, fail to hold the car, or?most dangerously?fail to release properly, causing the rear drum brakes to bind, overheat, and prematurely wear out the shoes.

Step-by-Step Diagnostic & Fix Guide

To restore a smooth, snap-back operation, you need to isolate and service the components systematically.

1. Isolate the Problem.
Before cleaning anything, you must determine whether the stickiness is in the cabin lever, the chassis linkage, or inside the brake drums themselves.

? Jack up the rear of the car and support it safely on axle stands.

? Crawl underneath and disconnect the clevis pins where the transverse rods meet the mechanical axle compensator.

? Test the wheels: Spin the rear wheels by hand. If they spin freely now, your issue lies entirely in the chassis linkages or cables. If a wheel is still binding, the mechanical wedge expander inside that specific brake wheel cylinder is seized or gummed up with old grease and brake dust.

2. Service the Chassis Pivots & Relay Lever
The most common culprit is the chassis-mounted relay lever positioned near the rear spring anchorage. It sits directly in the path of road spray.

? Remove and clean: Unbolt the relay assembly. Decades of old grease turn into a hard, glue-like paste. Thoroughly clean the pivot pin and bushes using brake cleaner or paraffin.

? Inspect the Clevis Pins: Check every single clevis pin along the rod linkage. If they are worn "oval" or deeply grooved, they will bind under tension. Replace any deformed clevis pins to eradicate slack and binding.

? Lubricate: Reassemble the pivots using a high-quality chassis grease or anti-seize lubricant.

3. Free Up the Axle Compensator & Transverse Rods
The compensator unit sits directly on the rear axle housing. It features balance levers designed to distribute equal pulling force to both rear wheels.

? Locate the balance lever oiling point (often overlooked during routine maintenance).

? Clean out the old grease and grit from the compensator sliding mechanism.

? Liberally apply penetrating oil to free up the mechanism, then pack it with a clean, light grease that won't readily trap road dirt. Ensure the transverse rods can move smoothly side-to-side without catching.

4. Flush and Lubricate the Inner Cables
The short cable from the dashboard pistol-grip and the cable leading down to the axle compensator can dry out, rust, and fray internally.

? Check if the outer conduit wraps are split or kinked. If they are damaged, water ingress has likely ruined them, and you will need new handbrake cables.

? If they are intact but stiff, disconnect both ends of the cables. Use a dedicated cable-lubricator tool (common in classic motorcycle maintenance) or fashion a small funnel out of tape around the top of the cable housing. Pour penetrating oil or thin chain lube down the cable until it runs out cleanly at the bottom.

5. Address Internal Cylinder Wedge Expanders
If the stickiness was isolated to the wheel itself in Step 1, you must pull the brake drums.

? Inside the late Girling fully hydraulic rear cylinder, the handbrake pushes a mechanical wedge slider that physically spreads the brake shoes.

? These sliders frequently jam up if the dust boots have perished, allowing brake dust and moisture inside.

? Carefully remove the shoes and dismantle the mechanical slider portion of the cylinder. Clean thoroughly and apply a microscopic film of high-temperature copper anti-seize or specialized brake grease to the sliding wedge tracks. Do not over-grease, as any excess will contaminate your brake linings.

Factory Setup Trick on Reassembly

According to original Austin Service Journals, when you are ready to bolt everything back together, follow this exact sequence to ensure the handbrake doesn't bind:
1. Leave the linkages slightly disconnected or loose.

2. Go to the rear backing plates and tighten the square-ended brake adjusters hard up against the drums so the wheels are completely locked.

3. Go underneath the car and pull all the slack out of the mechanical rods and cables until they are taut, then connect and split-pin your linkages.

4. Back off the square wheel adjusters exactly two clicks , or until the wheels spin completely freely.

This ensures that the linkage is perfectly tensioned relative to the exact position of the shoes, giving you a sharp, highly effective handbrake that snaps fully off when released.

[/quote]
_________________
Dellow Mk2, 1951 built, reg 1952.
Fiat 126 BIS
Cannon special [1996 registered. Built in 1950's]
----------------------------------------------
Ford Pop chassis, Ashley 1172 bodyshell, in pieces.

[alastairq]

[alastairq]

Sorry about all the glitches.

This forum format is , for me, on a PCpc, clunkier than my daily's front suspension.
_________________
Dellow Mk2, 1951 built, reg 1952.
Fiat 126 BIS
Cannon special [1996 registered. Built in 1950's]
----------------------------------------------
Ford Pop chassis, Ashley 1172 bodyshell, in pieces.

[ukdave2002]

Is wedge is already sitting too far into the expander at rest?
If previous adjustment has effectively pulled it halfway through its travel just to eliminate slack, you can end up with very little useful movement or force remaining.

[Ray White]

I suppose it all depends on how much of your time you feel can be given over to grovelling about on the floor under a car?.

If you have access to a four post lift in a garage then this is not too bad a job. If, on the other hand you only have small ramps and axle stands then ask yourself if this is really what you want to be doing with your life.

For a young person the job is quite a bit less stressful than for an old codger. If it were me, I would try finding someone else who can do the job for a reasonable sum and leave it to them.

No names, no pack drill.

[alastairq]

[Ray White]

[alastairq]

[Ray White]

I have not heard the engine run but apparently it is misfiring. Unfortunately, my friend is probably his own worst enemy as he is reluctant to accept well meaning help.