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E85 Hydraulic steering conversion part 1
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E85 Hydraulic steering conversion part 1
The P/S warning light come on in my 2003 Z4. My local garage said the column had failed. BMW wanted £2500 plus vat for new column. The car is only worth £3000 so not many options. Ergen in Sussex would convert to to hydraulic system for £2000 which was tempting but still quite a lot of money. I had read in the forum that two members in the UK had done the conversion. However they were no longer on the forum. Luckily for me one of our american cousins v8z4 had carried out the conversion in the states so I was able to contact him for help and assistance. After about 2 months I had gather enough information and parts to start the conversion. I will do this thread in two stages. This first one concerns the rack.
When BMW built the E85 they based it on the series 3 for the running gear. For some reason known only to themselves they did not use the same steering system but instead used the EPS which has caused no end of problems and was even the subject of a recall. Thankfully parts from the E46 series will fit.
The two racks compared. Pinions are very different.
The first part you will need is the E46 power steering rack with a purple tag. The purple tag refers to the badge on the rack which is purple in colour instead of silver. It has exactly the same turn to turn rate of 2.9 as the Z4. I bought a reconditioned one and some new tie rod ends total cost £200. If you are doing it this way this you will need to scavenge the tie rod nuts and cups from your old rack. The only thing wrong with the rack is that the pinion is smaller than the one on the Z4. The Z4 intermediate shaft will just not fit as it is too big. You will need the shaft from a Z4M which you can buy new from BMW for around £250. Ouch! With this shaft both couplings are the same size. What you could do is to get another Z4 shaft and get an engineering firm to swap the steering column pinion for the smaller shaft so that you will have one shaft with the couplings the same size. In a previous post concerning this the owner had merely removed the plastic guide cover and tightened up the joint to fit. I would strongly disagree . Either get the Z4M shaft or get the Z4 altered. v8z8 had a special one made up by a specialist.
the two shafts upper is the Z4M
the two shafts showing the difference in size.
For the first stage safely jack the car up and fix the steering straight ahead. Remove the key and lock the wheel. The wheel must not turn otherwise damage to the clock springs may occur. Remove the plastic undertray then the metal undertray. The rear four bolts point at an angle.Remove wheels. Remove tie rod ends. One came away easily while the other needed a bit of heat. Disconnect the intermediate shaft at the baulkhead, no need to remove the lower one , undo the two nuts and bolts holding the rack in place and simply remove the rack and shaft down.
Rack removed. Skid pan not removed but you need to remove it
You now need to assemble the new rack. As a rough guide the tie rod ends fitted onto the rack with about 20 turns. You can use the ones from your old rack but I would prefer you use new ones. You will need the tie rod nuts and caps as these were not supplied. You will need the black plastic cap on top of the pinion as the Z4 does not fit. The cap has a guide hole for the torq bolt so you know when the joint is engaged properly
You also need two torq bolts from BMW for the intermediate which are only £1 each. They have a blue coating to act as a lock and are single use only. Assemble the rack and get the rack into the neutral or straight ahead position. Offer it into place. A tight squeeze with the extra pipes on the rack but it does fit. Bolt into place. Now from inside the engine offer the shaft onto the upper steering pinion. It will only go one in one posion as there is a tab on the pinion. Don't push it fully home. from underneath line up the plastic cover to fit over the lower joint then once happy push it into position. As the shaft is sliding you can use this to place the joint so it lines up. Fit the old torq bolt not the new one. Now push home the upper joint and again use the old bolt. With the tie rods in place the whole thing should line up. Test from lock to lock. Once you are happy remove old bolts and torque new bolts into place. Mark the position of the bolts in yellow paint
new torq bolts note the blue film
Torque all remaining bolts. The first stage is now complete.
When BMW built the E85 they based it on the series 3 for the running gear. For some reason known only to themselves they did not use the same steering system but instead used the EPS which has caused no end of problems and was even the subject of a recall. Thankfully parts from the E46 series will fit.
The two racks compared. Pinions are very different.
The first part you will need is the E46 power steering rack with a purple tag. The purple tag refers to the badge on the rack which is purple in colour instead of silver. It has exactly the same turn to turn rate of 2.9 as the Z4. I bought a reconditioned one and some new tie rod ends total cost £200. If you are doing it this way this you will need to scavenge the tie rod nuts and cups from your old rack. The only thing wrong with the rack is that the pinion is smaller than the one on the Z4. The Z4 intermediate shaft will just not fit as it is too big. You will need the shaft from a Z4M which you can buy new from BMW for around £250. Ouch! With this shaft both couplings are the same size. What you could do is to get another Z4 shaft and get an engineering firm to swap the steering column pinion for the smaller shaft so that you will have one shaft with the couplings the same size. In a previous post concerning this the owner had merely removed the plastic guide cover and tightened up the joint to fit. I would strongly disagree . Either get the Z4M shaft or get the Z4 altered. v8z8 had a special one made up by a specialist.
the two shafts upper is the Z4M
the two shafts showing the difference in size.
For the first stage safely jack the car up and fix the steering straight ahead. Remove the key and lock the wheel. The wheel must not turn otherwise damage to the clock springs may occur. Remove the plastic undertray then the metal undertray. The rear four bolts point at an angle.Remove wheels. Remove tie rod ends. One came away easily while the other needed a bit of heat. Disconnect the intermediate shaft at the baulkhead, no need to remove the lower one , undo the two nuts and bolts holding the rack in place and simply remove the rack and shaft down.
Rack removed. Skid pan not removed but you need to remove it
You now need to assemble the new rack. As a rough guide the tie rod ends fitted onto the rack with about 20 turns. You can use the ones from your old rack but I would prefer you use new ones. You will need the tie rod nuts and caps as these were not supplied. You will need the black plastic cap on top of the pinion as the Z4 does not fit. The cap has a guide hole for the torq bolt so you know when the joint is engaged properly
You also need two torq bolts from BMW for the intermediate which are only £1 each. They have a blue coating to act as a lock and are single use only. Assemble the rack and get the rack into the neutral or straight ahead position. Offer it into place. A tight squeeze with the extra pipes on the rack but it does fit. Bolt into place. Now from inside the engine offer the shaft onto the upper steering pinion. It will only go one in one posion as there is a tab on the pinion. Don't push it fully home. from underneath line up the plastic cover to fit over the lower joint then once happy push it into position. As the shaft is sliding you can use this to place the joint so it lines up. Fit the old torq bolt not the new one. Now push home the upper joint and again use the old bolt. With the tie rods in place the whole thing should line up. Test from lock to lock. Once you are happy remove old bolts and torque new bolts into place. Mark the position of the bolts in yellow paint
new torq bolts note the blue film
Torque all remaining bolts. The first stage is now complete.
- Beedub
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E85 Hydraulic steering conversion part 1
wow!!! awesome stuff!! your going to love the feel of this setup!! its a really great feeling unit!
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E85 Hydraulic steering conversion part 1
Is some one going to offer this as a package deal fitted ????
I suspect it would be well received.
I suspect it would be well received.
- Jollyjoiner
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E85 Hydraulic steering conversion part 1
Looking forward to reading the next installment on this mod
2009 35i DCT silver
SLT mapped to 365bhp
SLT mapped to 365bhp
- Chris_D
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E85 Hydraulic steering conversion part 1
Bookmarked and eagerly anticipating all the progress updates ray!
Good luck mate
Good luck mate
E85 3.0i roadie (03) 'Benny'. E93 320d M-Sport Cabrio (11) 'Bob'.
'Always different, always the same.' John Peel on The Fall.
'Always different, always the same.' John Peel on The Fall.
- cj10jeeper
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E85 Hydraulic steering conversion part 1
Certainly does look like an interesting project. Look forward to seeing further instalments as you connect it up, sort out a PS pump, etc.
Good warning on the shaft size. With such a critical part it needs to be spot on, not just clamped up tight
Good warning on the shaft size. With such a critical part it needs to be spot on, not just clamped up tight
Jaguar F-Type 3.0 Supercharged V6 S, Stratus Grey, LSD, Active Exhaust, CF wheels, Performance brakes, Sports seats and mods ongoing
Gone but not forgotten Z4 3.0i SE Roadster ///M front, Red ///M leather seats, Aero sills
Gone but not forgotten Z4 3.0i SE Roadster ///M front, Red ///M leather seats, Aero sills
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E85 Hydraulic steering conversion part 1
Excellent stuff. Looking forward to the next part
M
M
- maxman
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E85 Hydraulic steering conversion part 1
A very comprehensive write up,looking forward to the next instalment .
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OnlineMr Tidy
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E85 Hydraulic steering conversion part 1
Great write-up OP.
One of the few failings of the E85 (or in my case E86) is the EPAS IMHO - my E46 with the hydraulic set-up has much better feel!
One of the few failings of the E85 (or in my case E86) is the EPAS IMHO - my E46 with the hydraulic set-up has much better feel!
Coupes because stunning!
Current - Silver Grey MC, Imola Red heated Nappa & carbon trim. Aeros, H & R Coil-overs, 224s, OE Strut brace, Nav, cup-holders, DSP Hi-Fi, pdc, cruise, MFSW, no CDV! E90 330i daily
Gone - Montego Blue
Gone - Ruby Black
Current - Silver Grey MC, Imola Red heated Nappa & carbon trim. Aeros, H & R Coil-overs, 224s, OE Strut brace, Nav, cup-holders, DSP Hi-Fi, pdc, cruise, MFSW, no CDV! E90 330i daily
Gone - Montego Blue
Gone - Ruby Black
- Ducklakeview
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E85 Hydraulic steering conversion part 1
Subbing...
I fancy this for mine, as a way of removing some of the twitchiness of the EPS setup.
Mike
I fancy this for mine, as a way of removing some of the twitchiness of the EPS setup.
Mike
- bladeowner
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E85 Hydraulic steering conversion part 1
Great write up
Wonder whether it would be possible to obtain/manufacture a split splined reducing collar for the shaft size difference?
Look forward to the next instalment.
Wonder whether it would be possible to obtain/manufacture a split splined reducing collar for the shaft size difference?
Look forward to the next instalment.
2004 Sapphire Black 2.5 SE Z4 SMG
- cj10jeeper
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E85 Hydraulic steering conversion part 1
Depends on the size difference but possible if of a high quality. I'd still be reluctant to have such a critical point with 2 set of splines and a single pinch bolt. Could be nasty if it failed..bladeowner wrote:Great write up
Wonder whether it would be possible to obtain/manufacture a split splined reducing collar for the shaft size difference?
Look forward to the next instalment.
Jaguar F-Type 3.0 Supercharged V6 S, Stratus Grey, LSD, Active Exhaust, CF wheels, Performance brakes, Sports seats and mods ongoing
Gone but not forgotten Z4 3.0i SE Roadster ///M front, Red ///M leather seats, Aero sills
Gone but not forgotten Z4 3.0i SE Roadster ///M front, Red ///M leather seats, Aero sills
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E85 Hydraulic steering conversion part 1
https://www.instagram.com/p/x7sXmPGE_r/ They offer it for £2000 fittedsticky wrote:Is some one going to offer this as a package deal fitted ????
I suspect it would be well received.
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E85 Hydraulic steering conversion part 1
Believe me I have spent many hours researching this issue. The intermediate shaft is part of the safety system designed to crumple in an accident. It is on a sliding shaft and the pinion on the Z4 is completely different to the E46 and the Z4M. I think the old safe option is to use the Z4M shaft which is available from BMW part number 32-30-7-836-809cj10jeeper wrote:Depends on the size difference but possible if of a high quality. I'd still be reluctant to have such a critical point with 2 set of splines and a single pinch bolt. Could be nasty if it failed..bladeowner wrote:Great write up
Wonder whether it would be possible to obtain/manufacture a split splined reducing collar for the shaft size difference?
Look forward to the next instalment.
- Machine monkey
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E85 Hydraulic steering conversion part 1
Depends on the size difference but possible if of a high quality. I'd still be reluctant to have such a critical point with 2 set of splines and a single pinch bolt. Could be nasty if it failed..[/quotecj10jeeper wrote:bladeowner wrote:Great write up
Wonder whether it would be possible to obtain/manufacture a split splined reducing collar for the shaft size difference?
Look forward to the next instalment.
In theory i guess you could get a splined slave made. But the only way i can see how it could be made would be wire cut. And the cost just wouldn't be worth it. There is only 1 mm difference between the 2 so a .5mm wall thickness. I am looking at other ways of doing it for my conversion. But what with work the and the baby i just haven't had time to look at it. I am hoping as the wife and baby are away this weekend i may get some time to work on my car or sleep!!