SLS to Coil Conversion
#1
01-16-2010, 06:19 PM
SLS to Coil Conversion
Hello Again,
I made a quick write-up on switching from SLS to Coils.
1. Ensure vehicle is in park and that the park brake up. Raise whichever side of the axle you wish by using the radius arm as the jack point.
2. Use the jack stand to rest chassis at the location shown.
3. Disconnect the speed sensor cable or if you have had the recall done meaning you have your wire connected to the SLABS ECU, you can just crawl underneath the rig and make the cable longer by giving it more slack cutting off the zip ties that secure it.
4. Remove brake caliper using a 12mm wrench and collect two brake pads. Careful where you rest the caliper. My jack was tall enough to let the caliper rest on the jack without putting stress on the brake line.
Now it should look like this
5. Using a 13mm wrench, remove the bump stop.
6. Position a 4 ton bottle jack or your standard LR vehicle jack between the chassis and axle. This will allow you to gain the required clearance needed to insert the spring without needing a spring compressor.
7. Now get ready to remove the airbag. Locate the two retaining clips on the top.
Left retaining clip
Right retaining clip
Remove the retaining clips.
8. Now to remove the air line you have two options. One is to remove the line before removing the bag, or option two, do it after you remove the bag. I think doing it after is easier but I did it before. I'll show you what I'm talking about in the next few steps. Third option is to cut the line so it depends what you want to do.
So using a small wrench loosen the nut. Then if you have small fingers continue removing the nut and disconnect.
Nothing happened when the line was removed. I was expecting pressured air from the line or bag to escape.
9. Pull the bag down and out of the top perch.
10. Turn the bag 90 degrees clockwise and pull out from the lower axle seat.
11. Remove height sensor.
12. Locate the two holes for the spring seat retaining bolts.
Grab your 10mm x 1.50 Tap
13. Run the 10mm X 1.50 tap through these holes to ease installation of retaining bolts. I didn't have the tap handle so I used a 1/4, 12 pt socket and my 3/8 drive.
I made a quick write-up on switching from SLS to Coils.
1. Ensure vehicle is in park and that the park brake up. Raise whichever side of the axle you wish by using the radius arm as the jack point.
2. Use the jack stand to rest chassis at the location shown.
3. Disconnect the speed sensor cable or if you have had the recall done meaning you have your wire connected to the SLABS ECU, you can just crawl underneath the rig and make the cable longer by giving it more slack cutting off the zip ties that secure it.
4. Remove brake caliper using a 12mm wrench and collect two brake pads. Careful where you rest the caliper. My jack was tall enough to let the caliper rest on the jack without putting stress on the brake line.
Now it should look like this
5. Using a 13mm wrench, remove the bump stop.
6. Position a 4 ton bottle jack or your standard LR vehicle jack between the chassis and axle. This will allow you to gain the required clearance needed to insert the spring without needing a spring compressor.
7. Now get ready to remove the airbag. Locate the two retaining clips on the top.
Left retaining clip
Right retaining clip
Remove the retaining clips.
8. Now to remove the air line you have two options. One is to remove the line before removing the bag, or option two, do it after you remove the bag. I think doing it after is easier but I did it before. I'll show you what I'm talking about in the next few steps. Third option is to cut the line so it depends what you want to do.
So using a small wrench loosen the nut. Then if you have small fingers continue removing the nut and disconnect.
Nothing happened when the line was removed. I was expecting pressured air from the line or bag to escape.
9. Pull the bag down and out of the top perch.
10. Turn the bag 90 degrees clockwise and pull out from the lower axle seat.
11. Remove height sensor.
12. Locate the two holes for the spring seat retaining bolts.
Grab your 10mm x 1.50 Tap
13. Run the 10mm X 1.50 tap through these holes to ease installation of retaining bolts. I didn't have the tap handle so I used a 1/4, 12 pt socket and my 3/8 drive.
Last edited by jycsalas; 01-16-2010 at 07:03 PM.
#2
01-16-2010, 06:22 PM
14. Make sure you have the tap straight up and down. Use oil to lube the tap. Working very slowly, start rotating the tap until you will feel it start cutting. Continue turning slowly and putting drops of oil. Once it has gone through, reverse it out.
15. Install the spring seat.
16. Remove the top bolt of the shock absorber to allow axle to be lowered further. If installing new shocks, then remove completely. This rig had new Bilstein shocks.
It should look like this
17. Grab your spring and the upper spring isolator. Make sure the direction of the spring is correct. The tighter coils need to be at the top.
18. Using the bottle jack, lower the axle until the spring fits under the upper spring seat.
19. Now you need to ensure the spring and isolator are positioned correctly under the spring seat.
20. Correctly installed.
21. Release pressure from jack to allow installation of top shock absorber bolt.
22. Refit bump stop
23. Refit brake caliper.
24. Refit wheel.
25. Reprogram slabs computer to coil springs using Autologic or Test Book diagnostic system (this will disable the air suspension system.)
26. Take out for a test drive.
If you can't make a trip to a dealer or shop, remove the SLS related relays and fuses. The SLS warning light will remain until it gets reprogrammed.
Enjoy...
15. Install the spring seat.
16. Remove the top bolt of the shock absorber to allow axle to be lowered further. If installing new shocks, then remove completely. This rig had new Bilstein shocks.
It should look like this
17. Grab your spring and the upper spring isolator. Make sure the direction of the spring is correct. The tighter coils need to be at the top.
18. Using the bottle jack, lower the axle until the spring fits under the upper spring seat.
19. Now you need to ensure the spring and isolator are positioned correctly under the spring seat.
20. Correctly installed.
21. Release pressure from jack to allow installation of top shock absorber bolt.
22. Refit bump stop
23. Refit brake caliper.
24. Refit wheel.
25. Reprogram slabs computer to coil springs using Autologic or Test Book diagnostic system (this will disable the air suspension system.)
26. Take out for a test drive.
If you can't make a trip to a dealer or shop, remove the SLS related relays and fuses. The SLS warning light will remain until it gets reprogrammed.
Enjoy...
Last edited by jycsalas; 01-16-2010 at 06:48 PM.
#3
01-29-2010, 12:47 AM
LIFT RESULTS AND PERFORMANCE
According to Atlantic British, the height of a P38 in standard ride height with stock tires measured from the ground to the top of the wheel well is 31-3/4” in the front, and 32” in the rear. With the OME 761 PS in front + 15 mm of trim packers and 781 PS in the rear, I measured 34-7/8” front and 35-3/4” in rear, with stock tires. This equates to a lift of 3-1/8” in the front and 3-3/4” in the rear. With BFG MT/KM 265/75/16 tires it measured 36-3/8” in the front and 37-1/4” in the rear. Please note that the stock coil springs in these kits are much shorter than the OME’s and that is why I got so much lift.
On-Road Performance: The OME springs ride great. Firm but not harsh and handles bumps and turns very well. Tracking at highway speeds is not as good as stock but definitely very very good for the amount of lift and the larger MT tires. I have not experienced any driveline vibrations at this moment and just returned from a 1900 mile trip to Colorado and the lifted P38 on MT’s handled the winding mountain roads very well. It also cruised pretty effortlessly on the highway. Road handling would be even better with an AT tire.
Off-Road Performance: I could not be happier. Ran three days of varied terrain trails in Ouray and Gunnison area with excellent results. On rocky trails, the P38 just walked up the rocks and obstacles, the articulation was excellent, and the axles rocked and rolled while the body stayed straight. Front approach and rear departure angles are also greatly improved. After a while, I would look for the most difficult line and the P38 just cruised through. The combination of the OME lift, MT tires, and rear traction control (95-98), front and rear on (99-01), made for quick work on moderate to difficult trails.
OTHER SPRING OPTIONS
In hindsight, I would have probably chosen a longer front spring so that I could get away from using trim packers. An option is to put 761 Driver Side (DS) springs in instead of the 761 PS, this would give you a slightly taller spring and maybe use less trim packers. 764’s could also be an option and would give you about 0.4” over my 761 PS + 15mm trim packer combination. I will probably go this route if I add a winch. I also don’t see a problem using 751’s in the front or 762’s in the rear if one is inclined to do so, and it would probably yield a very similar amount of lift.
CONCLUSION
I could not be happier on how the lift turned out, but will be looking into some longer shocks in the future. I am not a shock expert, so if anyone can provide more info that would be great. The P38 having a longer wheelbase (108”) makes for much better rear passenger room and the cargo area is also very large. With the coil spring lift, it drives great on the road, and it is also great off-road, plus no more EAS worries. This in my opinion, makes the already good P38 an even better all round vehicle. Add a pair of ARB’s, sliders, diff guards, winch, etc. and this would be one great trail vehicle. Hope this helps anyone interested, and hope to see more people modding the P38.
According to Atlantic British, the height of a P38 in standard ride height with stock tires measured from the ground to the top of the wheel well is 31-3/4” in the front, and 32” in the rear. With the OME 761 PS in front + 15 mm of trim packers and 781 PS in the rear, I measured 34-7/8” front and 35-3/4” in rear, with stock tires. This equates to a lift of 3-1/8” in the front and 3-3/4” in the rear. With BFG MT/KM 265/75/16 tires it measured 36-3/8” in the front and 37-1/4” in the rear. Please note that the stock coil springs in these kits are much shorter than the OME’s and that is why I got so much lift.
On-Road Performance: The OME springs ride great. Firm but not harsh and handles bumps and turns very well. Tracking at highway speeds is not as good as stock but definitely very very good for the amount of lift and the larger MT tires. I have not experienced any driveline vibrations at this moment and just returned from a 1900 mile trip to Colorado and the lifted P38 on MT’s handled the winding mountain roads very well. It also cruised pretty effortlessly on the highway. Road handling would be even better with an AT tire.
Off-Road Performance: I could not be happier. Ran three days of varied terrain trails in Ouray and Gunnison area with excellent results. On rocky trails, the P38 just walked up the rocks and obstacles, the articulation was excellent, and the axles rocked and rolled while the body stayed straight. Front approach and rear departure angles are also greatly improved. After a while, I would look for the most difficult line and the P38 just cruised through. The combination of the OME lift, MT tires, and rear traction control (95-98), front and rear on (99-01), made for quick work on moderate to difficult trails.
OTHER SPRING OPTIONS
In hindsight, I would have probably chosen a longer front spring so that I could get away from using trim packers. An option is to put 761 Driver Side (DS) springs in instead of the 761 PS, this would give you a slightly taller spring and maybe use less trim packers. 764’s could also be an option and would give you about 0.4” over my 761 PS + 15mm trim packer combination. I will probably go this route if I add a winch. I also don’t see a problem using 751’s in the front or 762’s in the rear if one is inclined to do so, and it would probably yield a very similar amount of lift.
CONCLUSION
I could not be happier on how the lift turned out, but will be looking into some longer shocks in the future. I am not a shock expert, so if anyone can provide more info that would be great. The P38 having a longer wheelbase (108”) makes for much better rear passenger room and the cargo area is also very large. With the coil spring lift, it drives great on the road, and it is also great off-road, plus no more EAS worries. This in my opinion, makes the already good P38 an even better all round vehicle. Add a pair of ARB’s, sliders, diff guards, winch, etc. and this would be one great trail vehicle. Hope this helps anyone interested, and hope to see more people modding the P38.
great instructions...
#5
08-01-2010, 08:53 PM
#6
08-01-2010, 09:56 PM
TReK
#7
08-04-2010, 12:11 PM
After replacing the SLS air bags with coil springs, is it sufficient to simply remove the SLS fuse? I realize the SLS instrument cluster light will stay on. But is it really necessary to have it reprogramed with Testbook? (One dealer wants $190 minimum to just open the door and the cost quickly rises from there if he needs to actually do anything, another dealer has openings 2-3 weeks out, and an indy has openings more than 3 weeks from now.)
#8
08-05-2010, 07:01 AM
Three Wheeling
Join Date: Apr 2009
Location: CT
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Nice instructions, thanks so much. Love the bottle jack idea.
wrp: you don't need to have it reprogrammed, but you should remove the fuse and the relay. after a while, I got tired of seeing the lights on the dash so I contacted atlantic british and they gave me the name of an independent shop that would reprogram it for me for a decent price. total cost at this independent shop: $40
wrp: you don't need to have it reprogrammed, but you should remove the fuse and the relay. after a while, I got tired of seeing the lights on the dash so I contacted atlantic british and they gave me the name of an independent shop that would reprogram it for me for a decent price. total cost at this independent shop: $40
#9
08-05-2010, 08:34 AM
Thanks, but after removing the SLS fuse the instrument cluster light still has not come on - I'll also remove the SLS relay.
And a comment on the coil conversion here: I just jacked up the frame on both sides at the same time, rather than jacking up the axle. The suspension is at it's fully extended position, and I compressed each spring only about 1/2" so it could fit into position. (I didn't want to disturb the shock bolts since they looked to be nicely rusted in position) Also, it's a good time to replace brakes/rotors because if you wait too long rust blends everything together.
And a comment on the coil conversion here: I just jacked up the frame on both sides at the same time, rather than jacking up the axle. The suspension is at it's fully extended position, and I compressed each spring only about 1/2" so it could fit into position. (I didn't want to disturb the shock bolts since they looked to be nicely rusted in position) Also, it's a good time to replace brakes/rotors because if you wait too long rust blends everything together.
#10
08-14-2010, 09:49 PM
