Rear Axle Leaks

From Holdenpaedia
Jump to: navigation, search

Page created by T May 16th 2007:

Back to Gearboxes Transmissions and Differentials

Rear Axle Breather removed from the car. Click to enlargen. Photo by HQ SS.

==Rear Axle Leaks:==

===Differential Breather:=== Whether the car uses a Salisbury or a Banjo Differential, the Rear Axle will a have breather fitted to it near the diff centre. The breather allows air pressure built up inside the Axle Housing to escape.  

On some offroad vehicles, the breather is connected to a rubber hose that exhausts high above the road wheels to prevent the ingress of dirt.

===Breather Blockage:===

Rear Axle Breather removed from the car. Click to enlargen. Photo by HQ SS.
Driving on dusty or muddy roads causes dirt to be thrown up around the rear axle which can block up the Breather. If the Breather blocks, pressure built up in Axle cannot escape and Oil will be forced out the Pinion and Axle seals. The buildup of pressure over a number of uses of the vehicle can result in loss of diff oil and ultimately a diff failure. It is important to periodically check that the breather is clean and can allow pressure to flow out of it.

===Rear Axle Lubrication:===

 If you remove a driving axle out of the Rear Axle Housing of a car that's just been driven a short distance, you will see that diff oil is clinging to the axle like honey and has formed a spiral that runs from the diff centre out towards the wheel bearings. The Pinion Gear (connected to the tailshaft yoke) lives permanently immersed in Oil. The lower half of the Crown Wheel (the large gear that the pinion turns) is permanently immersed in Oil. As the Crown Wheel rotates, the teeth on it pick up Oil and carry it to the highest point where the Oil cascades onto the Hemisphere (the diff centre, where the 4 small gears are). From the Hemisphere, the Oil gravitates along the Axles until it reaches and lubricates the Wheel Bearings. From here it drains back along the bottom of the Axle Housing until it reaches the centre of Axle Housing where it is picked up by the Crown Wheel again.

HR Banjo breather. Click to enlargen. Photo by HQ SS.

===Pinion Seal Leaks:===

The Pinion Seal can leak, with age, if the Breather becomes blocked, if the surface of the Yoke that it runs on becomes scored, or if the Bearing associated with it has excessive wear.

===Axle Seal Leaks:===

The Axle Seals can leak, with age, if the Breather becomes blocked, if the surface of the Axle that they run on becomes scored, or if the Bearings associated with them have excessive wear.

===Apparent Leaks:===

VB Sals Breather. Click to enlargen. Photo by HQ SS.
Sometimes the diff centre can appear to be leaking when it is actually covered with oil that has been thrown back there from the Gearbox, Engine or a leak from the Welch Plug in the front Tailshaft Yoke. A Brake Wheel Cylinder can leak and seem like an Axle Seal. Inspect the Brakes before attempting any expensive diff work without good reason.

10 Bolt Salisbury Rear Axle. Note the Breather is covered in Red Dust. Click to Enlargen. Photo by Perth Mick.

 

Axle Tube separating from the Diff Housing on a Salisbury Rear Axle. Note the Breather has an extension tube fitted. Photo by SoudWB. Click to Enlargen.

 

===Links:===

===Terms:===

Terms

Back to Gearboxes Transmissions and Differentials