Vent ABS System

[WesBrooks]

Hi all,
Whats the standard procedure for venting the '94 ABS system (RRC) before disassembly?

Are the brake fittings a standard thread rather than tapered? I was toying with the idea of buying a job lot of small bolts to screw back into the holes once brake pipes are removed to keep the internals clean after disassembly.

Edited May 31, 2020 by WesBrooks

[elbekko]

You mean take the pressure out of the accumulator? Press the pedal 20ish times with the ignition off.

[WesBrooks]

Just make sure the brake fluid doesn't spray when I open up the circuit. I guess that includes thw accumulator. The non abs disci I stripped squirted and that doesn't have one does it?

[Snagger]

If the pump is disabled, then every time you apply the pedal, the accumulator will lose a little pressure, so leave the ignition off and pump the pedal as elbekko said.  Once that’s been done, it should be depressurised, but I’d start by slowly undoing the bleed nipples on the valve pack and accumulator.  It’s worth unplugging the pump just to avoid accidental pressurisation should you forget while whorking.

[WesBrooks]

Thanks, will do that.

Pump, block, and controller unplugged. No front loom or fuseboxes left on the vehicle! 🙂

[Bigj66]

On 6/1/2020 at 8:58 AM, WesBrooks said:

Thanks, will do that.

Pump, block, and controller unplugged. No front loom or fuseboxes left on the vehicle! 🙂

Are you reusing the brake system Wes?

[WesBrooks]

Hope so yes. I have the fall back of the non-abs disco 1 system if needed.

[Maverik]

On 6/1/2020 at 8:33 AM, Snagger said:

If the pump is disabled, then every time you apply the pedal, the accumulator will lose a little pressure, so leave the ignition off and pump the pedal as elbekko said.  Once that’s been done, it should be depressurised, but I’d start by slowly undoing the bleed nipples on the valve pack and accumulator.  It’s worth unplugging the pump just to avoid accidental pressurisation should you forget while whorking.

More out of surprise and interest than anything, but there's a hydraulic accumulator in the brake system?

[WesBrooks]

Yup. On the classic (and maybe top model disco 1s?) it is a seperate sphere component next to the valve block, and on the P38s I believe it was integrated onto the valve block.

[WesBrooks]

Here's the valve block and accumulator up against the bulkhead, drivers side on a Range Rover Classic...

('scuse my foot. I was getting a 12V charger from the garage!)

 

[Maverik]

Thanks, not see that in a brake system before.

[elbekko]

Still separate from the valve block on the P38, it's together with the pump.

[WesBrooks]

Close but no cigar for me today! 😄

Remembered it being connected to something!

 

[Bowie69]

42 minutes ago, elbekko said:

Still separate from the valve block on the P38, it's together with the pump.

Yup exactly, can bed on a Classic to replace pump and separate accumulator -one way of getting slightly newer second hand parts to keep yours running!

[geoffbeaumont]

If it was me, if the ABS system from the classic didn't work, I'd be looking to find one that did not fall back on the non-ABS system from the discovery. 

Having owned vehicles with both, the RR ABS system is massively better, even if the ABS isn't functioning. More powerful, arguably better feel. 

[Bowie69]

Agreed, Classic brakes are great.

[WesBrooks]

I certainly intend to keep the ABS. Don't think the '94 (14CUX) had traction control did it?

Where the V8 disco disc brakes that poor?

 

[Bigj66]

I replaced the pressure switch about a year before you bought it.

Brakes were great on it and it had both TC and ABS👍

[Snagger]

TC is only on the rear axle, though, which is a pity.

[WesBrooks]

Softdash era classics definitely come across as customer funded test mules! The ABS, traction control, intermediate Serp V8s, and air suspension were all early but similar versions to that seen in the P38s?

 

Edited June 8, 2020 by WesBrooks

[geoffbeaumont]

On 6/7/2020 at 8:13 AM, WesBrooks said:

I certainly intend to keep the ABS. Don't think the '94 (14CUX) had traction control did it?

Pretty certain it was an option - don't think it was ever standard - but my '93 had TC. As Snagger says, rear axle only on the classic (and earlier P38s) - but it's still pretty effective.
 

4 hours ago, WesBrooks said:

Softdash era classics definitely come across as customer funded test mules! The ABS, traction control, intermediate Serp V8s, and air suspension were all early but similar versions to that seen in the P38s?

I'd say that's an entirely fair comment! Started before the softdash (from '93? EAS wasn't available before that, don't think TC was. The intermediate serp V8s were later).

[WesBrooks]

Would using a hand vacuum to clear the brake fluid cause any issues?

I realise that it won't be an issue of just draining the caliper bleed nipples but wanted to make sure the obvious answer isn't likely to cause issues like the intuative way of  rotor arm removal on V8s!

 

[elbekko]

It might not work. Maybe for the front brakes, but you'll want the valves in the valve block to open up while bleeding. So either using the pedal with the ignition on, or opening them with diagnostics (at least on the P38).

[Snagger]

On 6/8/2020 at 8:52 AM, WesBrooks said:

Softdash era classics definitely come across as customer funded test mules! The ABS, traction control, intermediate Serp V8s, and air suspension were all early but similar versions to that seen in the P38s?

 

Certainly for the EAS.  It took me two years to find my soft dash Tdi Vogue (non-SE) - factory coil sprung, cloth manual seats (no crackEd leather and no trouble prone switches, motors or ECUs), no leaky sunroof, no huge fuel bill, and an R380 that doesn’t sap too much of the Tdi’s lesser performance.  Not that many of this spec about.

[Snagger]

19 hours ago, WesBrooks said:

Would using a hand vacuum to clear the brake fluid cause any issues?

I realise that it won't be an issue of just draining the caliper bleed nipples but wanted to make sure the obvious answer isn't likely to cause issues like the intuative way of  rotor arm removal on V8s!

 

Should be fine for removing the fluid, but not necessary.  But for bleeding, there is a very specific sequence in the manuals, and it is done by the pump.