Hybrid_From_Hell Posted March 31, 2008 Share Posted March 31, 2008 Well, With my bent steering box, I have had a rummage and have a good spare, Whilst I think around fitting this I have thought about what I could do to beef things up for the future. The things so far that have crossed my mind ( ) on 'Hydro Assisting' the steering on my 90 are : Pros. Hydro Assist seems to be both "Road Legal" And not something that is a huge problem (vs say 'Large BHP' and 3 link ) I have strengthed the steering with Sumo / Dar antibend bracketry bars on both links etc Hydro assist will save the box and give much greater power to the steering Cons No really good qulaity off the shelf solution (spoken to David at Llama who is still in development on this ) Where to mount Ram ? Front or even behind axle How to mount ? RAM Specs ? Lag delay if PAS Pump not upgraded ? What pump could easiliyish have the upgrade to ? Method of plumbing up, some have been done without even removing the box, ? May move the breakages to somewhere else in the line - ie ripping out TRE ? If so ideas for beefing up any seemingly weak bits ? So Thoughts as to design, things to consider part nos of suitable ram, lengths ideas etc ? If you had a clean sheet of paper what and how might you do it ? Even more so with the benifit of already having done an install, pros cons of what you have ? Post up puics diagrams ideas ..... Discuss Nige Quote Link to comment Share on other sites More sharing options...
white90 Posted March 31, 2008 Share Posted March 31, 2008 http://forums.lr4x4.com/index.php?showtopi...hl=hydro+assist http://forums.lr4x4.com/index.php?showtopi...hl=hydro+assist http://forums.lr4x4.com/index.php?showtopic=20628&hl= Quote Link to comment Share on other sites More sharing options...
Steve 90 Posted March 31, 2008 Share Posted March 31, 2008 I think as far as pro's and cons are concerned you have it about right. I must say that the hydro assist on my truck is the one modification I really wouldn't want to be without. Its brilliant, You can turn the steering with just the palm of your hand. Soaking wet muddy hands struggling to find grip on the steering wheel to turn the heavy steering is a thing of the past. The latest version running on the top of the pitman arm is fantastic. The truck even drives nicely on the road now. The previous version with the ram on to the axle end of the drag link worked fine off road but I was always worried about damaging the ram or hoses as they were down in the line of fire a bit. Also the drag link would flip flop as you went from one direction to the other, Not only resulting in a slight bend in the end of the ram but on the road giving a horrible feeling where everytime you turned the steering it was normal at first then the ram would catch up causing it to go very light. Believe me, Its not nice. This is the third version. It still needs a slight alteration, when I steer left handed at full lock it destroys the lock stop. I need to move the ram about 45mm so it runs out of travel just as it hits the stop which sould solve the problem. For some reason (maybe because its not an equal cylinder in both directions) I don't seem to have any touble in the other direction. I originally tried to fit it behind the axle on the track rod, this was possible but the ram I had at the time was too big. Looking back I'm glad I didn't as after destroying 3 track rods in not much time I like to run a track rod guard now and this would all get a bit complicated. Plus the ram would be back in the thick of it again just waiting to get damaged. I have fitted a ZF74 pump, The original P.A.S. pump off the TDi seemed to have plenty of power but was quite slow. If you went to swerve around something the steering just wouldn't keep up, Especially at low engine speed. You could live with it but its far better with a better pump. Just one word of warning, The ZF pumps you find on a lot of german cars use the same housing but don't have anywhere near the same figures as the ZF74. The people who do our hydraulic, P.A.S. stuff say that ZF use the same casting for 95% of the pumps they do (including the 300tdi I think) they said the ZF74 must be for some sort of industrial application as no car P.A.S. pump has anywhere near the rating given for the ZF74. I'm not saying the P.A.S. pumps found on these cars are not good enough tho, They may well be, definitely better than the V8 and 200tdi ones. I will fully recommend it, I am tempted to go full hydro, but just because I want to get rid of the steering box so I can cut the front off the chassis. Quote Link to comment Share on other sites More sharing options...
filthy boy Posted March 31, 2008 Share Posted March 31, 2008 It's not on a LR axle but the idea might be useful. Front mounted double ended ram, acts as track rod and is legal (as approved last week by the SVA man ). We have a 4 bolt Saginaw box (Jeeps and Rolls Royce) tapped. The real key is the pump. We are pushing out 8.5 gallons per minute at high pressure (3000 psi working, 9000 psi burst hoses). About 3 turns lock to lock and 35 to 40 degrees of lock. As I said not a Land Rover but don't see why the ideas could not be applied. Tim Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted March 31, 2008 Author Share Posted March 31, 2008 Hmmm Filthy Boy / Steve 90 - info dimensions and or pics would be good ? Whats the flow rates of the 2x LR pumps ie the older cast unit vs the tin v8 type - are the the same flow with just differing pipes or differning flows ? Nige Quote Link to comment Share on other sites More sharing options...
Steve 90 Posted April 1, 2008 Share Posted April 1, 2008 I dont have a great deal in the way of dimensions handy at the minute but here's a couple of pic's. This does seem to work brilliantly and is very quick and easy to do. Cheers. Steve. Quote Link to comment Share on other sites More sharing options...
Steve 90 Posted April 1, 2008 Share Posted April 1, 2008 Also because the ram does not have equal bore size in both directions the fluid level would vary quite a bit from one extreme of lock to the other and the std reservoir didn't have enough capacity to cope with it. I used a steel reservoir of a bedford TL which would be ideal and has a filter inside it. If you can find one an early RR/90 tin reservoir would be perfect. Quote Link to comment Share on other sites More sharing options...
marek Posted November 26, 2008 Share Posted November 26, 2008 hi im trying to put hydro assist on my 110 but haveing touble with finding the ram size. not to good at maths soo.... ive found the lama 4x4 kit but their rod ends seem very small an dont think they will hold out much, does anyone have the ram dimensions or know where i can get a ram with like an m20 rose joint end? i was also thinking of fitting it on the axle as if my PAS linkages fail at least i may have sometype of steering even tho itll be carp., any ideas?? nice set up above by the way marekhydro steering help!!! Quote Link to comment Share on other sites More sharing options...
DiscoDino Posted November 26, 2008 Share Posted November 26, 2008 I've been running hydro assist since 2004...it isn't perfect, but it helps through... Ram is from Rockstomper in the US, mounted in the normal Defender steering dampner location, & the pump is from a GMC truck (believe it is a Saginaw pump)...the issue isn't the ram, the mounting, the pump or anything else...the issue is the steering box itself...I don't believe it is made for a high flow rate and therefore limits the amount of pressure/volume heading to the ram...does that make sense? My next step is to see how to bore the steering box, put the assist set-up on my 36"ed daily driver, and go full hydro on my 42"ed truggy Quote Link to comment Share on other sites More sharing options...
Steve 90 Posted November 26, 2008 Share Posted November 26, 2008 I've been running hydro assist since 2004...it isn't perfect, but it helps through...Ram is from Rockstomper in the US, mounted in the normal Defender steering dampner location, & the pump is from a GMC truck (believe it is a Saginaw pump)...the issue isn't the ram, the mounting, the pump or anything else...the issue is the steering box itself...I don't believe it is made for a high flow rate and therefore limits the amount of pressure/volume heading to the ram...does that make sense? My next step is to see how to bore the steering box, put the assist set-up on my 36"ed daily driver, and go full hydro on my 42"ed truggy Funny you should say that, Ive been having some problems too! http://forums.lr4x4.com/index.php?showtopic=34210&hl= Quote Link to comment Share on other sites More sharing options...
DiscoDino Posted November 26, 2008 Share Posted November 26, 2008 Yeah - time to go full hydro and get the appropriate orbital valve Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted November 26, 2008 Author Share Posted November 26, 2008 would it be logical / fair to say that with the problem you have lock to lock this gets worse the bigger your tyres ?. ie would the issue be reduced when 34" replaced the 36" ?? Just a thought (for mine) as still thinking, but need to finish the cage and a couple fab jobs favours that I promised to do for others Nige Quote Link to comment Share on other sites More sharing options...
DiscoDino Posted November 27, 2008 Share Posted November 27, 2008 Definitely easier for smaller tires...36 to 34 isn't THAT dramatic, so I wouldn't say that you'll be THAT MUCH safe...when I went from 36 to 42, I fel the difference... Quote Link to comment Share on other sites More sharing options...
will_warne Posted November 27, 2008 Share Posted November 27, 2008 would it be logical / fair to say that with the problem you have lock to lock this gets worse the bigger your tyres ?. ie would the issue be reduced when 34" replaced the 36" ??Just a thought (for mine) as still thinking, but need to finish the cage and a couple fab jobs favours that I promised to do for others Nige Nige, the main issue with most of the setups seems to be that, because you can't get much fluid through the LR steering box, you are limited to the speed at which you can move the ram. Either you need to do something about the steering box or use a ram with a smaller effective area. Tyre size should have no effect on the speed issue (unless you are mucking about with the ram location to get more ram travel per degree of steering lock....) My take on it is you need to ditch the LR steering box and go for something else - the question is what's the best option out there??? Given most of us who want to run this sort of setup are only running hydro assist to avoid C&U issues the steering box is just there to provide a mechanical linkage. Two of my thoughts which need some looking into are: - DII box. Any good??? - Defender MANUAL steering box with a straight through orbital valve. It'll take some setting up but it appeals to me because it is effectively full hydro steer (and could be converted to full hydro in minutes) but ticks all the boxes. It'll be fiddly to set up correctly, though..... What do people reckon? There are other options out there (Saginaw box being one of the ones at the top of the list) but using a steering box that's easier to get hold of in this country would be a bonus. Quote Link to comment Share on other sites More sharing options...
DiscoDino Posted November 27, 2008 Share Posted November 27, 2008 Agree on your tire size thinking, but the larger the tires, the more effort, the less speedy...at least that's my impression... That non-assist Defender Box is a good idea...any numbers show flow rate? Quote Link to comment Share on other sites More sharing options...
will_warne Posted November 27, 2008 Share Posted November 27, 2008 Agree on your tire size thinking, but the larger the tires, the more effort, the less speedy...at least that's my impression...That non-assist Defender Box is a good idea...any numbers show flow rate? Fair point, it's you slowing the steering down rather than it actually being impossible to go quickly. I know a few people who have had issues with the latter - the steering box literally won't flow enough fluid so it's actually stopping the steering from being turned more quickly. Not sure about flow rates yet - I haven't done any sums. Having not done all my steering homework yet I may be off the mark here but surely be adjusting the pressure relief valve and flow rate (via a finely tunable valve just after the pump) you could setup the hydro assist to perfectly match the mechanical steering. Quote Link to comment Share on other sites More sharing options...
simonr Posted November 27, 2008 Share Posted November 27, 2008 Another possible solution. This ia the steering rack from a Range Rover Sport It's not terribly clear - but you can see where the steering wheel connects to and below that the valve gear. There is a shaft which comes out of the valve which in turn drives the rack. The valve connects to a double ended ram inside the rack body via external pipes. If one were to put the valve in between the steering column and the regular steering box, it would switch the flow to a secondary ram just as well as drilling the original box. I suggest the RRS rack because they are fast, quick ratio - and hence high flow, but many other cars use a similar arrangement. There are even one or two where the valve assembly is completely separate from the rack. This is probably safer than trying to port the original box - or drill it to connect a secondary ram - and more likely to work! Si Quote Link to comment Share on other sites More sharing options...
will_warne Posted November 28, 2008 Share Posted November 28, 2008 Another possible solution. This ia the steering rack from a Range Rover Sport It's not terribly clear - but you can see where the steering wheel connects to and below that the valve gear. There is a shaft which comes out of the valve which in turn drives the rack. The valve connects to a double ended ram inside the rack body via external pipes. If one were to put the valve in between the steering column and the regular steering box, it would switch the flow to a secondary ram just as well as drilling the original box. I suggest the RRS rack because they are fast, quick ratio - and hence high flow, but many other cars use a similar arrangement. There are even one or two where the valve assembly is completely separate from the rack. This is probably safer than trying to port the original box - or drill it to connect a secondary ram - and more likely to work! Si Si, this was basically the line I was thinking along. B) The biggest issue is matching the hydro steer element and the manual steer element - this will require some fine tuning. My reasoning for thinking about a manual LR box is they're cheap, bolt straight on and strength shouldn't be an issue as the hydro ram should be dealing with all the shock loads. The only downside I can see is the speed of the box however an in line quicker either between the valve and the steering box or between the valve and the steering wheel would sort that - on the full hydro systems I've tried there has never been an issue with steering being heavy or lacking in power so there shouldn't be any issues with the latter. That way you can also change the steering ratio to suit what you're doing - quick ratio for speed stuff, super light standard ratio for technical stuff. Quote Link to comment Share on other sites More sharing options...
filthy boy Posted November 28, 2008 Share Posted November 28, 2008 Spent months looking into this, including axle mounted racks. Problem with separate servo and box is that without a lot of tuning and cleverness they will fight each other giving some nasty feedback through the steering. Discussed this with some US suppliers who had spent a lot of time and $ trying to make this work with no luck. Just get a proper steering box and a high flow pump! Tim Quote Link to comment Share on other sites More sharing options...
Lara Posted November 28, 2008 Share Posted November 28, 2008 My take on it is you need to ditch the LR steering box and go for something else - the question is what's the best option out there??? Given most of us who want to run this sort of setup are only running hydro assist to avoid C&U issues the steering box is just there to provide a mechanical linkage. Two of my thoughts which need some looking into are: Will, I have read and read and read the TUV paperwork and have asked the question so many times it hurts, but no one has ever shown me the section where the TUV requests you to have this "mechanical linkage" "metal linkage" or any other specific link! Hydraulic "IS" mechanical, Hydraulic (if filled with Mercury) "IS" a metal link, a "metal link" it couldn't be written or described, even if it was! Unless anyone can show me the relevant section as I may possibly have missed it (although I think not) I have asked so many "experts" and even the SVA themselves, they also said that they had no problem if it conformed to "their regs" but could or would not tell me what did or didn't Anyone show me the section and wording? other than "a man who knows told me" Only problem for a full hydraulic as far as I can read and foresee is self centering. and I reckon I could sort that if I put my head to it. Lara Quote Link to comment Share on other sites More sharing options...
simonr Posted November 28, 2008 Share Posted November 28, 2008 I recently had a chat with one of the (very friendly & helpful) chaps at VOSA regarding SVA - and although we didn't cover this specifically - in answer to most questions he said that if it looks like it will do the job, it will pass. If not, you will have to prove that it can otherwise it will fail. OK, that's rather subjective but I can see where they are coming from. It's just to try to stop people doing stupid things but at the same time not asking us to subject everything to proper (expensive) testing. Likewise, I've not found anything which specifically prohibits full hydro steering. If the servo pump is one which provides force-feedback - then it should be capable of self centering. One could just wind up the amount of toe-in to increase the centering force? I think the potential issues with it are two fold. Firstly, the position of the wheels drifts over time with respect to the steering wheel which could give rise to you thinking the wheels were straight when they are not. OK - a bit tenuous as they don't drift much unless pretty worn. The second is that with PAS, you have a fail-over in the event of pressure loss. Much the same thinking as dual circuit brakes. Full hydro has no backup. I have seen hydro servo pumps with two pumps back to back on the steering wheel - presumably to drive two actuators. This might provide sufficient fail-over capacity? I suspect at the end of the day that they might turn round and say it will pass so long as you can prove it's safe - which seemed to be the catch-all answer to most of my 'more unusual' questions! In answer to my last post. I agree there are potential problems having two servo control systems back to back - more possibility for oscillation due to unintentional feedback loops. The solution (as suggested by Will) is to use a manual box and just use the ram/valve for the power assistance. Si Quote Link to comment Share on other sites More sharing options...
will_warne Posted November 28, 2008 Share Posted November 28, 2008 Will,I have read and read and read the TUV paperwork and have asked the question so many times it hurts, but no one has ever shown me the section where the TUV requests you to have this "mechanical linkage" "metal linkage" or any other specific link! Hydraulic "IS" mechanical, Hydraulic (if filled with Mercury) "IS" a metal link, a "metal link" it couldn't be written or described, even if it was! Unless anyone can show me the relevant section as I may possibly have missed it (although I think not) I have asked so many "experts" and even the SVA themselves, they also said that they had no problem if it conformed to "their regs" but could or would not tell me what did or didn't Anyone show me the section and wording? other than "a man who knows told me" Only problem for a full hydraulic as far as I can read and foresee is self centering. and I reckon I could sort that if I put my head to it. Lara I'll have to do some digging on this... Self centring - load reaction orbital valve working on a balanced system (2 way ram or opposed rams for those trying to follow) and plenty of castor Quote Link to comment Share on other sites More sharing options...
Lara Posted November 28, 2008 Share Posted November 28, 2008 A very good answer Simon, Exactly as I have found from various SVA people, Glad someone also agrees that they can not find any specifics in the rule book, was beginning to think it was my eyes With regards to a backup though, I don't see why it is any different than a ball joint failing? no backup there either! As you say though, the return always being different and the lack of self centre may be issues. Think Tim's answer is the easiest though if people "must" have a steering box! Lara Quote Link to comment Share on other sites More sharing options...
dollythelw Posted November 28, 2008 Share Posted November 28, 2008 my system self centres just as nicely as any "normal" car Ive ever driven as for the "back up" debate, I drove 80kms of forest with no pump at all......... kinda puts paid to the "oh your steering doesnt work with a dead engine/broken pump" marlarky, having said that even if you show someone the steering working with a dead engine they will still go with bloke down the pubs opinion so whats the point Quote Link to comment Share on other sites More sharing options...
Lara Posted November 28, 2008 Share Posted November 28, 2008 my system self centres just as nicely as any "normal" car Ive ever drivenas for the "back up" debate, I drove 80kms of forest with no pump at all......... kinda puts paid to the "oh your steering doesn't work with a dead engine/broken pump" malarkey, having said that even if you show someone the steering working with a dead engine they will still go with bloke down the pubs opinion so whats the point Mmmmmm, Need to chat you up about self centre then matey!!! You in on Sunday? Might be over your way ) If people are simply after easier steering then either simply fit a higher pressure pump (not flow) Or one of these http://www.howeperformance.com/accessories-new.htm Steering Speeder/Reducer 1.5:1 Ratio Lara Quote Link to comment Share on other sites More sharing options...
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