Brake bleeding procedure

I'm going to need to bleed the brakes on my JB74 at some point. Is there a specific procedure to follow at all? I know with some cars it is just the normal way you'd do any vehicles. But others like my p38 Range Rover have a very specific brake bleeding procedure that you really do have to follow if you want a good pedal at the end of it.

Thanks.

Bleed brake farthest from Master cylinder and then brake on same line. Ditto on other line.
Info. from w.shop manual.

Roger

In order to bleed the brake fluid from the ABS module you should really use an OBD code reader that is capable of opening the valves in the module.

Is that necessary in a Jimny?  It's not normal procedure in most cars, and there aren't many non-ABS cars left on the road. 

Main dealers often just suck out the fluid in the reservoir and refill with fresh stuff, which is almost completely useless but (a) you're not going to get internal corrosion during the 3 years that most owners use main dealer service and (b) the fluid LOOKS as if it's been changed (lighter colour) so no-one complains.  I dread freeing off the bleed screws on used cars, most of which probably haven't been touched since the factory.

rogerzilla wrote:

Is that necessary in a Jimny?  It's not normal procedure in most cars, and there aren't many non-ABS cars left on the road. 

Main dealers often just suck out the fluid in the reservoir and refill with fresh stuff, which is almost completely useless but (a) you're not going to get internal corrosion during the 3 years that most owners use main dealer service and (b) the fluid LOOKS as if it's been changed (lighter colour) so no-one complains.  I dread freeing off the bleed screws on used cars, most of which probably haven't been touched since the factory.

An interesting point. Routine brake fluid bleeding serves to remove and replace brake fluid that might have an unacceptably high water content. As well as preventing vapour lock this also reduces the chance of corrosion within the hydraulic system. The ABS module is complex and, in my opinion, susceptible to damage through corrosion. It therefore makes sense to bleed out the old brake fluid within the ABS module.
This does assume that an ABS module has a reservoir of fluid that is only cycled when the ABS operates. I do not know enough about the JB74 ABS module to know if this applies. Maybe someone else has the answer to this.

It will depend on the exact design of the ABS unit.  They have an internal fluid reservoir - probably one for each brake circuit, in fact - but whether this is open to the brake circuits when the engine is off and the system unpowered, I don't know.

This article suggests that "it varies" but you can, more often than not, bleed as normal.

Bleeding ABS brakes

There's an interesting workaround involving making the ABS operate by actually provoking a skid, which may be a reasonably safe possibility in an off-road vehicle.  Just find a gravel track.

I am aware that it is disastrous to empty the system of fluid on some cars, as air in the ABS module of those can only be purged by electronic means (meaning the car may need to be trailered to a dealer!) but I've never had to work on one.  Due diligence pays here if you're changing a brake hose!

Doctorchris wrote:

In order to bleed the brake fluid from the ABS module you should really use an OBD code reader that is capable of opening the valves in the module.

Do you have the procedure for this if this is what is needed? Thanks.

The w/shop manual shows the ABS module as part of the system, but does not mention the need for an OBD reader, so I assume that it is not needed.

Roger

300bhpton wrote:

Doctorchris wrote:

In order to bleed the brake fluid from the ABS module you should really use an OBD code reader that is capable of opening the valves in the module.

Do you have the procedure for this if this is what is needed? Thanks.

I have only read about this procedure, I've never carried it out. You would need to obtain an OBD code reader with An ABS module purging capability for the Jimny JB74. The code reader is plugged in and ABS bleeding selected on the screen. As far as I know you then follow the bleeding instructions on the screen. However it does look as if hardly anyone bothers with this procedure, not even the Suzuki dealers.