75 steering rack

[deano]

From what I understand there are two power steering racks. The first is in the earlier 75TS, 2.5 and the 90. It has the balance lines and the rack itself is a little thinner I believe. Thats what I have in the car at the moment. Only one balance line is open which is what I did last thursday trying to solve the problem. The other lines are sealed. I cant get to them without jacking the engine up with is something I dont have time for at the moment. The other rack is slightly thicker and is internally balanced in some way. Thats what was fitted to the 75 3.0 and it'll most likely be rebuilt and find its way back into the car before PI in december. It looks like thats the one in greg gordans pic

Sheldon, It'll be interesting to compare the steering. It cant stay the way it is at the moment. The weight difference isnt really worth worrying about in my mind. Maybe 15 kilos which I can deal with. An angle grinder can get a hell of a lot more weight out of the car. If its worth it for feel, I may consider risking another night of misery under the car on jack stands.

David, I think its the way to go in the long run. I never had properly functioning steering in my car. The power rack felt like it was starting to fail which is why I ditched it. Now I miss it.

Another intersting thing is my cars lack of straight line speed. Compared to last year, the car felt so much slower. I didnt even reach the rev limiter on third down the straight. Maybe that crash involving the sump earlier this year knocked the gate open and all the horses ran away... I'm going to be busy this summer. But all in all, I'm really happy with the car at the moment.

[MD]

If anybody is contemplating a typical Alfa track car with RWD and under 3 litres without using massive slicks, do this test before you make your mind up whether to install manual or power steering.

In a quiet street or abandoned car park, move at 50-60kph straight ahead. With the steering wheel at the 12 o'clock position, as quick as you can, move it between 11 o'clock and 1 o'clock and back to 12 o'clock again as if you are swerving to avoid another car that has perhaps dived infront of you.

Do this test with power a assisted RWD car and preferably the same ( or similar )car with a manual rack.If you are doing the manoeuvre fast enough you should see a big difference between the cars how far they each deviate from the straight ahead direction and ultimately whether you managed to avoid a timely contact with the imaginary car in front or not.

In this context, the difference in rack performance is like chalk and cheese.

[Duk]

Deano, there's definitely something wrong with what you've got. No PS in my daily driver for the last 3 years and I'm still waiting for the massive guns.

Sheldon I think the red line is the communication between the boots, if you look at the pic of mine it looks the same as Gregs except the housing on the end of the rack at the left has been rotated 90 degrees so the rack boot balance port is at the top.  Is your boot balance line actually connected to the boots?  

If you pull the rack apart and pull out the main seal you don't need any balance lines (apart from the rack boot balance line)

Scott

All of this talk about non power steering conversion has me thinking about the same for my car. Is anybody running large caster angles, wide wheel (8" with 215/225 width tyres) with enough offset to take up most of the 75 flared wheel arches?

[ALF750]

An old thread but thought I'd share the steering rack swap job for posterity, plus I have some questions (RHD 1991 75TS).   Old rack was leaking, put Lucas stop leak in, it got better but then catastrophically failed while parking (on the stop, bypass mode?).   I took the belt off the pump and drove on for several months.   I was given a spare rack when I bought the car that needed rebuilding.  Got that done so decided to have a go at it this weekend.    Removal needed loosening of the RH engine mount and jacking the engine up as much as possible to get the rack out the RHS.  Once removed I found the rack differed slightly from my rebuilt replacement!   Very close, but the replacement did not have the plastic equalising tube (?) from the pinion area to the opposite end (original rack 7830 955 117..1736230768 vs. rebuilt rack 7830 955 107..0391150485).   I can't find where this alternative rack came from, yet, maybe an earlier model going by the lower number?   Is it internally equalised like Deano aid above? Anyway, I put it in being an optimist! (no trouble to change back, really.....).   Refitting was opposite of removal, lower the engine, do everything up, fill with oil, bleed (do you need to?) and start engine, turn wheel several times to burp it - and it seems to work.   But, when driving it seems to be vague and wanders a bit.   Maybe it still has air in it, maybe my eyeball wheel alignment is the culprit, but I'm out of daylight and energy for today (job was done on the shed floor with jack stands, about 7 hours all up).
So, can someone advise me where this replacement rack came from/source vehicle?

thanks.

[jazig.k]

Ha, Lucas destroyed my old rack just like that. They refunded me for the cost of the fluid though.

Sounds like the same rack I pulled from both of my 3lt 75's. No external balance line, it's all internal. Can check numbers when I get home if it's bugging you...

Eyeball wheel alignment won't work out well... You'll need to go get that sorted out or learn how to string line the car if you want to DIY.

Did you refit it and rerun the PS or convert it to a manual rack?

[ALF750]

Yes, proper alignment is on the cards, just ran out of time.   I kept the PS as I have 205/45-16 wheels and smaller steering wheel, plus my wife drives it.   With just the pump fan belt off I found it good to drive apart from tight manoeuvring.   If it was solely my drive I'd go manual with a more standard diameter steering wheel.  If you couldcheck the numbers that might fill in some gaps, but don't stress it if it is a trouble jazig.  thanks.

[Colin Edwards]

Just wondering if this non-assisted rack will fit a 75 3.0?

https://www.okp.de/xtc2/75/Milano/50-Chassis/Steering/Short-exchange-steering-rack-2-25-turns-Alfetta/Giulietta/75::23779.html

Any one have experiance with the OKP product?
Not cheap!!! Just a design excercise at the moment - looking at repairing or replacing a slightly leaking power assisted rack.

[bazzbazz]

So you're thinking of gutting the new unit and transferring it to the old P/S unit to get the 2.25 turns?

[Duk]

2.25 turns! That's a full turn reduction compared to a PS rack.
It'd be good to know more about it.

Quite amazing as I was thinking about this very same thing today. 

[105gta]

It will fit just fine, the only modification needed is to move the drivers seat to the other side of the car and flip the dash board over with all the pedals etc... other wise a straight swap!

[Colin Edwards]

I have contacted OKP requesting they advise if a RHD version is available.
Looking at feasibility of doing away with PS.

[Colin Edwards]

OKP confirm LHD only!

[simmi1983]

I manualised my TS rack. Took off the punp, all the kibes, capped the ports and greased the bar. On is 2nd racing season and no probs at all. Gives great feedback and accuracy.  Love it.!

[deano]

Hey Colin,

I have a different opinion 9 years later having originally asked the question and doing it. I now think converting a power rack to a manual one is probably the biggest waste of time and money you can pump into a 75.

If your car is a late 3.0 it'll have the thicker and internally equalised rack so take it out, take to prestige power steering in Thomastown, spend the $600 to get it rebuilt and chuck it back in. Heat is what kills them so a bigger cooler for track work gives them a longer life.

If your pump is crap and you're getting the slight loss of assistance on quick direction changes get it rebuilt or lose the aircon and run a 164 pump which is a bit of dicking around I'm told.

In terms of feel I think we need to come to terms with the fact that a modern power 997 911 rack puts even the manual alfetta rack to shame in terms of feel. It's not the cars strong point and never will be. The manual 3.2 rack made my 3.0 feel like a 1965 mustang to drive. I think it's something we need to deal with but can be improved with other mods etc. A manual alfetta rack is better than a power 3.2 per rack so if you want better feel it's best to deal with the 3.6 turns.

There are so many other areas to invest money to improve a 75 such as some horse power given a slightly modified 3.0 with a ts box is only golf gti quick if that in a straight line. With 175-180 atw makes them quick enough by modern standards! Exhaust, front brakes, uprights, shorter gearing etc etc. Pet hate for me is a loose isostatic mechanism but each to their own!

Cheers
Dean

[Duk]

In this day and age of CNC machines, coming up with a suitable right hand drive, power steering equipped, faster ratio steering rack should be very doable.
Or maybe we could fudge something together???

So given the speed increase (2.2 turns instead of 4 turns(!) for the non-power steering rack. 3.25 turns for the power steering rack) that the OKP supplied rackand pinion has, I'd guess that there is sufficient room inside the pinion housing to accommodate a significantly larger diameter pinion.

So to get improvements and keep costs down, maybe a pinion from another rack could be found?
Some previous lookage showed that some/most/all Commodore steering racks were made by ZF.
Earlier (atleast to the VS Dunnydores) had what looked like, pretty long steering arms (something that MUST be kept in mind when comparing steering racks!). So maaaaaaaaaybe the pinion out of a Commodore rack could provide a suitable increase in pinion diameter and fit into the Alfa housing???
As a comparison, the steering arms on an R32 Skyline are about half as long as the Alfa's steering arms, but the Skyline would have (going by memory here......from an S13 Silvia...........) 2.5 turns or less, lock to lock. So while the Skyline and Silvia had fewer turns lock to lock than the Alfa, because of the shorter steering arms, the actual gear ratio inside the Alfa's steering rack would be higher (Well, actually it'd be LOWER! Basically the Alfa's rack would provide more rack movement per turn) than the Nissan's!).

Now getting a larger diameter pinion into the housing obviously isn't going to work with the stadard rack in there.
So I was thinking maybe, juuuuuuuuust MAYBE, new bushes could be made with an offset in them to lower the standard rack inside the housing.
If this could be done, it'd keep the cost of the whole thing down substatially.
This would probably introduce some bumpsteer into the steering, but that's fixable.
Again, lowering the original steering rack inside the housing via offset bushes is a MAYBE.

The other, more obvious solution, is to have a new rack produced with the teeth machined deeper into the rack shaft.
Given that car manufacturers build to a price rather than a recipe, starting with a higher quality piece of material rather than trying to machine the original Alfa rack to suit, would be a good idea.
Too many unknowns to walk that path.

So that raises an important question: What material to make these parts from?
4140 alloy steel would seems like a decent choice, but more input would be great.
If both the rack and the pinion were made from the same material, would that cause problem (gauling)?

So who has a disassembled steering rack that they could take some up close and personal piccies of?
Who else can chime in with helpful input?

Increasing the steeing response is a very doable thing for these cars. Doing it and doing it well without spending a fortune, is the challenge.