Bigj66 Posted August 21, 2020 Share Posted August 21, 2020 Has anyone fitted a P38 power steering box to the outside of their chassis and had a drag link made up to connect to the series swivel arm? If so what was the length of the drag link from the centre of the swivel arm to the centre of the steering box arm with the arm pointing straight ahead? Mine measures 970mm but Gwyn Lewis supplies them off the shelf and says they should be 1015mm. It’s a big difference. My wheels are parallel to the chassis and the steering arm is 90 degrees to the axle. Quote Link to comment Share on other sites More sharing options...
David Sparkes Posted August 21, 2020 Share Posted August 21, 2020 20 minutes ago, Bigj66 said: ... what was the length of the drag link from the centre of the swivel arm to the centre of the steering box arm with the arm pointing straight ahead? ... Mine measures 970mm but Gwyn Lewis supplies them off the shelf and says they should be 1015mm. It’s a big difference. Surely you are measuring to the wrong place, 'the centre of the swivel arm'? The drag link should go from the steering box arm to the front hole (not the centre hole) of the passenger side swivel arm. I have no idea what length difference this makes, I am just reacting to the curious description. Regards. Quote Link to comment Share on other sites More sharing options...
Bigj66 Posted August 21, 2020 Author Share Posted August 21, 2020 42 minutes ago, David Sparkes said: Surely you are measuring to the wrong place, 'the centre of the swivel arm'? The drag link should go from the steering box arm to the front hole (not the centre hole) of the passenger side swivel arm. I have no idea what length difference this makes, I am just reacting to the curious description. Regards. Apologies, I should have used the proper terminology. I’ve measured from the centre of the hole in the pitman arm on the box where the ball joint passes through to the centre of the forward most hole on the swivel steering arm attached to the passenger side swivel housing. The track rod is connected to the rear hole on the steering swivel arm. The bit I’m uncertain about is whether the pitman arm should be pointing forward at 90 degrees to the axle when measuring or at an angle as that will impact the length of the drag link. Quote Link to comment Share on other sites More sharing options...
missingsid Posted August 22, 2020 Share Posted August 22, 2020 Can you not find the centre of the travel by finding out how many turns you have lock to lock as this needs to be the straight ahead point. I am assuming (as I don't know) that the arm only fits on the steering box shaft in one place? Or at least one obvious place? I would expect that to be the 90 deg position as well but this would help confirm. Quote Link to comment Share on other sites More sharing options...
Bigj66 Posted August 22, 2020 Author Share Posted August 22, 2020 34 minutes ago, missingsid said: Can you not find the centre of the travel by finding out how many turns you have lock to lock as this needs to be the straight ahead point. I am assuming (as I don't know) that the arm only fits on the steering box shaft in one place? Or at least one obvious place? I would expect that to be the 90 deg position as well but this would help confirm. The pitman arm hasn’t been off the box so it should still be in the correct position but I’ll try it lock to lock in case the straight ahead position isn’t the central one. I just thought I’d ask about first in case others had come across it. On the rear of the box above the steering column UJ there is what looks like an alignment mark and with the pitman arm facing straight ahead this Mark is also in a top centre position. Although this may be unrelated, it did seem to make sense for checking wheel alignment. Quote Link to comment Share on other sites More sharing options...
Snagger Posted August 22, 2020 Share Posted August 22, 2020 When I fitted the P38 PAS to my 109, I used the P38 drag link cut down to suit. I just had the inside of the cut end tapped by a local engineering shop (Hogarth, who are the owners of the Partiot brand of accessories) as I didn’t have the right tap myself (the boss was always very friendly and helpful to me). It worked a treat. I don’t have dimensions, but given that I already had the Discovery front axle on there, they wouldn’t be much use to you anyway. I just set the steering and wheels straight ahead, loosely fitted the upper end of the link and the lower rod end isn’t he swivel arm and marked up the rod to show about 1/2” of threads for adjustment. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted August 22, 2020 Share Posted August 22, 2020 This shows a pic of how to center the box : http://www.mez.co.uk/page122.html Quote Link to comment Share on other sites More sharing options...
Bigj66 Posted August 22, 2020 Author Share Posted August 22, 2020 12 minutes ago, Bowie69 said: This shows a pic of how to center the box : http://www.mez.co.uk/page122.html Cheers, I think the clue may be in this: “Then I centred the steering box by rotating the input shaft until the marker on the side of the input shaft aligns with the arrow on the steering box.” I have that mark facing upwards, 90 degrees from this. I’ll align as that photo and measure again. 1 Quote Link to comment Share on other sites More sharing options...
Snagger Posted August 22, 2020 Share Posted August 22, 2020 Count the rotation from lock to lock, just to make sure the collar is on the right position of the shaft. Quote Link to comment Share on other sites More sharing options...
Bigj66 Posted August 22, 2020 Author Share Posted August 22, 2020 All sorted and hopefully this info will help others in the future. 3.75 turns lock to lock on the P38 box so just a tad under 1.9 turns to the centre. That aligns the pointer with the V notch on the inside face of the box and places the pitman arm pointing in roughly the 1 o’clock position when viewed from behind. Re-measuring in this position gives the correct 1015mm distance centre to centre for the drag link ball joints. 1 Quote Link to comment Share on other sites More sharing options...
Gazzar Posted August 22, 2020 Share Posted August 22, 2020 Good. I had it in the back of my mind that the arm wasn't at 90 degrees when the steering was straight ahead, glad you caught that. The correct right hand tap isn't terribly dear, so cutting down a longer track rod is a viable option. 1 Quote Link to comment Share on other sites More sharing options...
Bigj66 Posted August 22, 2020 Author Share Posted August 22, 2020 2 hours ago, Gazzar said: Good. I had it in the back of my mind that the arm wasn't at 90 degrees when the steering was straight ahead, glad you caught that. The correct right hand tap isn't terribly dear, so cutting down a longer track rod is a viable option. Yeah it isn’t straight, Gwyn just sent me a photo from one of his customer’s setup. 1 Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted August 22, 2020 Share Posted August 22, 2020 Great , glad it helped! 1 Quote Link to comment Share on other sites More sharing options...
missingsid Posted August 22, 2020 Share Posted August 22, 2020 I briefly scanned that adjustment guide and the statement that he loosend off all the tie rod clamps and went for a drive really worried me! But glad that you have a point of reference that gives you the confidence to set it up. Quote Link to comment Share on other sites More sharing options...
s3v8 Posted January 10, 2023 Share Posted January 10, 2023 On 8/22/2020 at 5:00 PM, Snagger said: When I fitted the P38 PAS to my 109, I used the P38 drag link cut down to suit. I just had the inside of the cut end tapped by a local engineering shop (Hogarth, who are the owners of the Partiot brand of accessories) as I didn’t have the right tap myself (the boss was always very friendly and helpful to me). It worked a treat. I don’t have dimensions, but given that I already had the Discovery front axle on there, they wouldn’t be much use to you anyway. I just set the steering and wheels straight ahead, loosely fitted the upper end of the link and the lower rod end isn’t he swivel arm and marked up the rod to show about 1/2” of threads for adjustment. Is the tube the correct diameter and will the tap of a series 3 track rod end fit? Looking to do the same and this sounds like the easiest method. Quote Link to comment Share on other sites More sharing options...
Snagger Posted January 10, 2023 Share Posted January 10, 2023 I think it was, but it is a long time since I did it. It took about five minutes for me to cut to cut and about the same for them to tap, and I don’t remember them drilling it. It maybe that I reused that end’s P38 ball joint, but in that case, that fit the steering arm without issue - they appear to use the same size and pitch taper from SII to the latest Defender, DII and P38. No idea about the later vehicles. Quote Link to comment Share on other sites More sharing options...
pete3000 Posted January 10, 2023 Share Posted January 10, 2023 TRE threads are different to original 88/109 but the taper for the tre is the same. Quote Link to comment Share on other sites More sharing options...
Bigj66 Posted January 12, 2023 Author Share Posted January 12, 2023 My standard S3 TRE fits the P38 drop arm taper. I did buy a set of grease-able TREs from Gwyn Lewis with the two rods but they’re still standard fit. Quote Link to comment Share on other sites More sharing options...
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