ABS retro fit

[landroversforever]

14 minutes ago, FridgeFreezer said:

Interestingly, Tom Sheppard in his more recent book was trucking about the desert in a G-Wagen which has as much articulation as a shopping trolley but does have a rear locker, and if anyone knows sand driving it's him.

I think G's have lockers front and rear from the factory.

[mad_pete]

It’s not like you don’t get at least one wheel on the ground and as long as it goes round I think you are literally good to go. 🙂

[elbekko]

15 hours ago, Snagger said:

That’s what I’d hoped - the Wabco system in the soft dash only has rear ETC, which is a pity.  For what I do with that car, ETC would suffice, but it has struggled with the front in snow.  It’s a pity that the valve block is incompatible with the P38 ECU, Elbekko.  Any idea if it’s plausible to fit the P38 valve block to a Classic?  I’d imagine the sensors could be a problem, though brake lines should be OK.

You'd have to convert to single-line front calipers. And I have no clue if the pressures are matched at all, it's basically changing to a (potentially very) different master cylinder. Sensors I think will be the least of your worries, it just needs a digital road speed, and the 4 ABS sensors (which I doubt have changed).

[Gazzar]

Are any of the early Freelander modules viable options?

[FridgeFreezer]

3 hours ago, Gazzar said:

Are any of the early Freelander modules viable options?

Don't see why not, they're compact and I think at least one of them is a standalone unit as they were optional fit early on.

[Snagger]

23 hours ago, elbekko said:

You'd have to convert to single-line front calipers. And I have no clue if the pressures are matched at all, it's basically changing to a (potentially very) different master cylinder. Sensors I think will be the least of your worries, it just needs a digital road speed, and the 4 ABS sensors (which I doubt have changed).

I can't remember for sure, but I think my RR already has single line front calipers.  If I'm not mistaken, 300Tdi era RRCs and Discoverys have that, the twin line system being on the 200Tdi (and earlier RRCs).  I used 300Tdi single hose calipers from an non-ABS donor on the 200 Discovery axle for my 109 to avoid the extra hoses and retain the old pipe layout on that.

John and Gaz, are the Freelander systems similar to the Defender and Discovery system in using a conventional master cylinder that then goes through a self-contained modulator block, rather than the very different pedal and actuator system on the ABS RRCs and P38?  I have never looked under the bonnet of a Freelander, so the vehicle is a bit of a mystery to me.

[Snagger]

On 6/11/2019 at 9:12 PM, FridgeFreezer said:

I can believe that for many systems, including the older ones prior to Terrain Response where it didn't know what surface you were on and therefore couldn't make smart choices about how to behave, and I can well believe that once everyone "knows" that ETC doesn't work in sand & pulls the fuse, that's what they'll do forever no matter the vehicle.

It may well be that just pulling the fuse is as good as anything anyway, especially if the local spec stuff has factory lockers (which some did).

Interestingly, Tom Sheppard in his more recent book was trucking about the desert in a G-Wagen which has as much articulation as a shopping trolley but does have a rear locker, and if anyone knows sand driving it's him.

The local guys modify their vehicles, lockers and tyres being the very first things that go on.  I understand the Jeep Wrangler Rubicon to be relatively unusual in having them from the factory, and it's very popular with the duners (and pretenders) here.  The very rich locals favour G-Wagens (rarely used by expats here).  Those that like more expedition and camping type driving here go for the bigger vehicles, usually the big US or Japanese pickups,  so tend to alter a fair bit as they have a lot of weight and long wheel bases.  One of the locals is very pleased with the results of fitting both axles and the LT230 on his 110Tdci with Ashcroft ATBs (which would be good with a spinning tyre still having resistance in sand, and the Defender's basic ETC breifly activating to trigger the ATBs and then backing off if they get a wheel lift).  I can't help thinking full lockers would be much better for the sand, though.

[elbekko]

1 hour ago, Snagger said:

I can't remember for sure, but I think my RR already has single line front calipers.  If I'm not mistaken, 300Tdi era RRCs and Discoverys have that, the twin line system being on the 200Tdi (and earlier RRCs).  I used 300Tdi single hose calipers from an non-ABS donor on the 200 Discovery axle for my 109 to avoid the extra hoses and retain the old pipe layout on that.

My 300TDi Classic has dual line calipers. The D1 300TDi didn't. It's an easy swap, but still.

Again, my biggest issue with all this would be line pressure differences from having a different master cylinder. The Freelander system could work, as it's a standalone valve block with a separate master. I think the D2 as well?

[Snagger]

5 hours ago, elbekko said:

My 300TDi Classic has dual line calipers. The D1 300TDi didn't. It's an easy swap, but still.

Again, my biggest issue with all this would be line pressure differences from having a different master cylinder. The Freelander system could work, as it's a standalone valve block with a separate master. I think the D2 as well?

The D2 certainly is - if it's not the same system as the late Defenders and late D1, then it's very similar.  The RRC ABS is so much better that I wouldn't go to the Discovery system just for the front ETC.  My 109 has the 300 Discovery brakes all round, including master, servo and biasing valve, but I'm not really interested in fitting it to that - I want ATBs.

[Niels Peter Kofoed]

When retro fitting ABS to an older Defender 110 SW (e.g. 1991), will the old Swivel Housing need to be changed or will the upper swivel pin fit directly? 

I know that the swivel ball will need to be replaced,

[landroversforever]

I reckon it will want changing. The earlier type has a railko bush in the top so the upper swivel pin sits in a cup shaped bush so there isn't any line of sight to the CV bell.

[Bigj66]

Interesting topic this as I’ve always wondered if it’s possible to replace a standard servo and master cylinder with a pump and valve block from an ABS vehicle but without using the ABS or TC?

Ive seen it done on old Fords but not Landrovers.

[Mo Murphy]

1 hour ago, Bigj66 said:

Interesting topic this as I’ve always wondered if it’s possible to replace a standard servo and master cylinder with a pump and valve block from an ABS vehicle but without using the ABS or TC?

Ive seen it done on old Fords but not Landrovers.

What's the benefit Bigj66 ?

Mo

[Bigj66]

46 minutes ago, Mo Murphy said:

What's the benefit Bigj66 ?

Mo

For me it’s the better pedal feel that the pumps give compared to the servo and master cylinder. I had this on my soft dash and it was night and day compared to a servo setup. Same as an aftermarket electric brake booster, quite common in the States.

[Mo Murphy]

I see, thanks for explaining that 👍

Mo

[landroversforever]

Interesting! 

[Bigj66]

13 minutes ago, Mo Murphy said:

I see, thanks for explaining that 👍

Mo

Just to clarify, it was standard with TC and ABS on my Rangy but I’ve heard of just the electric pump being used on its own on other makes such as Ford but not any from Landrover.

[Snagger]

9 hours ago, Bigj66 said:

For me it’s the better pedal feel that the pumps give compared to the servo and master cylinder. I had this on my soft dash and it was night and day compared to a servo setup. Same as an aftermarket electric brake booster, quite common in the States.

The system used on Defenders and D2 uses a conventional master and servo routed through a remote valve block and pump unit.  Maybe that’s why it’s so horrible - the worst elements of both systems. The RRC and P38 systems have a pump and accumulator, so are proper powered brakes.

[Bigj66]

4 minutes ago, Snagger said:

The system used on Defenders and D2 uses a conventional master and servo routed through a remote valve block and pump unit.  Maybe that’s why it’s so horrible - the worst elements of both systems. The RRC and P38 systems have a pump and accumulator, so are proper powered brakes.

Do you think it would be possible to delete the TC and ABS function and just use the pump?

[Snagger]

From the RRC or P38 system?  Probably, if you are able to reprogramme the ECU.  On the RRC, you have a Waco pump and separate accumulator with a pressure switch to trigger the pump to recharge the accumulator.  The P38 has a combined unit which is neater and probably more reliable.  That bit could be made to work without an ECU.  The RRC callipers and discs were standard for the era, same as for non ABS vehicles, and those all had equal hydraulic  pressure through their systems right up to the pint the bias valve in the rear lines did their job, where fitted (I think 110s didn’t have them, but Discovery certainly did, RRC probably, and I think 90s had some sort of valve that used inertia to adjust the biasing).  So, disabling the valve block to have the valves to each corner closed or open as appropriate to normal conditions, I guess it’d work.

[elbekko]

Disabling TC is just snipping a wire. ABS is a bit more difficult, without power the system only has the emergency backup braking on the front brakes.

Maybe you could rig the valves to just open with the ignition feed or something, but it sounds sketchy.

[Bigj66]

2 minutes ago, Snagger said:

From the RRC or P38 system?  Probably, if you are able to reprogramme the ECU.  On the RRC, you have a Waco pump and separate accumulator with a pressure switch to trigger the pump to recharge the accumulator.  The P38 has a combined unit which is neater and probably more reliable.  That bit could be made to work without an ECU.  The RRC callipers and discs were standard for the era, same as for non ABS vehicles, and those all had equal hydraulic  pressure through their systems right up to the pint the bias valve in the rear lines did their job, where fitted (I think 110s didn’t have them, but Discovery certainly did, RRC probably, and I think 90s had some sort of valve that used inertia to adjust the biasing).  So, disabling the valve block to have the valves to each corner closed or open as appropriate to normal conditions, I guess it’d work.

I was thinking about binning the ECU and just using the pump and accumulator from a P38 without the ABS block. Yes, you’d need to install a bias valve to get the balance set up correctly and then....

 

 

 

 

Stick it in a Series with discs all round 😬

[Snagger]

If it remember correctly, the pedal push rod and accumulator are connected directly to the valve block, so you’d have to retain it.  But you could replace the valves with plugs or remove plungers as required to ensure ports are kept open or closed as appropriate.  I don’t know how much of the power brake part of the system is dependant on an ECU, though - I only suspect that  the pressure switch would be enough with a simple relay to control the pump;  I don’t know if there is something more complex that needs more regulation.

[Bigj66]

2 minutes ago, Snagger said:

If it remember correctly, the pedal push rod and accumulator are connected directly to the valve block, so you’d have to retain it.  But you could replace the valves with plugs or remove plungers as required to ensure ports are kept open or closed as appropriate.  I don’t know how much of the power brake part of the system is dependant on an ECU, though - I only suspect that  the pressure switch would be enough with a simple relay to control the pump;  I don’t know if there is something more complex that needs more regulation.

The Ford systems just required power via a relay and the accumulator provided the reserve in case of power failure. I presume that’s how the system is designed on a P38.

Found some diagrams of a similar system on Range Rovers.net

 

[Snagger]

I think it’d work if you have the ABS release return line and ETC supply line valves locked closed (or replaced by plugs).  I think the master cylinder is part of that valve block, thought I may be mistaken - I can’t go and take a look.  It may be a separable module.  It could be a real can of worms for legal issues, though.  A simpler power brake system from an non ABS vehicle would probably be the safer way to go.