How To: Front & Rear Suspension Change, Aftermarket Coilovers Adjustment

Prelude

Since achieving my goals drag wise I’ve shifted focus to getting my car ready spec wise for some track action. As such the first thing needing doing in my mind was my suspension – not because my current Koni Shocks with Eibach Springs combo was worn, more because they were inherited when I bought my car and I’ve never been happy with how low it’s been.

Since fitting my Rota GTR 18’s I’ve experienced arch rubbing under hard cornering, over some bumps and more so when the car is fully laden because of the combination of the low ride height and the lower offset wheels filling out the arches more. The handling was sub-optimal in my opinion because of the super lowness, as seen here:

It has been an understeery mess like this when trying to really push on but the ride was at least comfortable. I’m more of a function over form kinda guy (remember that for my engine bay shot later ) so I wanted to raise the ride height slightly and stiffen things up a little on the road for backroad blasts whilst still maintaining decent ride quality and giving me the ability to stiffen things up further when going on track.

Aftermarket Coilovers seemed to fit the bill so I started looking around at what was on offer. Many such Coilover kits are extremely track focussed with very high spring rates and harsh damping and ultimately they are only at home on billiard table smooth track tarmac which indeed you’ll more often than not find a stock suspension’d car would thrash a car with such suspension down your average imperfectly surfaced UK backroad.

After searching around for a more sensible fast road / track setup I found the HSD HR Monotube Coilovers seemed to fit the bill at a very attractive price point of £682 delivered from the guys at www.driftworks.co.uk who have the European distribution rights – I ordered just before Xmas and had them in a couple of days as promised by PhilMorrison on here J

HSD Product blurb from their website at www.hsdcoilovers.com :

 

What are HSD Coilovers?

 

http://www.hsdcoilovers.com/img/HSD600-AllFour2.jpg

 

HSD Coilovers are the ‘own brand’ Coilovers of HD Systems, a company with over 20 years of experience with Monotube dampers and the manufacturers behind the Coilovers of some of the very best suspension brands worldwide.

 

HSD Coilovers use a very well respected and proven Monotube damper design combined with high quality hardware. This level of quality and performance is usually found on much more expensive suspension products. This is high end competition winning suspension available direct from the factory at affordable prices.

 

Due to the excellent handling characteristics of our Monotube dampers, HSD Coilovers give a supple, sporty and perfectly damped ride. They soak up bumps and jolts effortlessly, yet firm up when needed to give exceptional roadholding and handling on fast road and track. Cheaper aftermarket dampers use a twin-tube design with low pressure gas whereas our Monotube damper design uses large diameter pistons and a much higher gas pressure to better stabilise the oil within, even under extreme and prolonged use.

 

So with that it was time to fit them with the help of my ace mechanic Dad who’d finally been freed from household DIY hell to do more fun stuff . Given the procedure in Toyota’s workshop manuals on suspension change is a little long winded I figured I’d do a write up to show how a proper time-served experienced decent mechanic (technician actually but nobody seems to appreciate the difference between a mechanic and an MVT other than those in the trade) goes about things and hopefully anyone reading this can save themselves a bunch of time as a result on regular suspension removal and fitting and roughly what Coilovers need set to for a sensible ride height on our cars. Apologies in advance for the quality of some of the pics but it’s hard in awkward positions in the darkness of wheel arches!

1. Get the car in the air using a good jack then secure it onto an axle stand under the chassis leg. We did it one corner at a time as you can see in the pics. Tools needed for the job include deep sockets, spanners, locking long nose pliers, ratchets, a Samson bar and as long a lever as you can lay your hands on for maximum leverage. Use WD40 to soak any bolts / nuts along the way for an easy life and use copper grease when putting things back together to make refitting and future removal easier – it’s just good practice! The Coilovers themselves:

2. First up we tackled the Rear. Once the wheel is off you can see the job in hand:

3. From the front of the hub you can see it’s tight in there but as the upper wishbone is shaped to one side of the shock absorber it’s a relatively straightforward job compared with the front:

From the hub face:

4. There is one long bolt which holds the shock absorber to the hub assembly, held captive at the other end by a nut. Here we can see one end and a ratchet with socket on the bolt head ready to undo:

5. A close up from an under car perspective showing what needs to be done to get the bottom of the shocker freed up. A spanner on the nut end and you use one against the other to get the bolt undone:

Close up:

Link spanners together for extra leverage as necessary:

6. You need to take the load off the bolt to get it out so use a jack under the hub assembly to compress the shock a little:

7. Now to tackle the other end of the shock absorber. In the boot you need to take out the carpet and other trim covering the rear suspension turrets. It’s pretty obvious how to do that so we’ll just skip to showing the 3 nuts that need undone to free the shock absorber here:

8. Now from the hub face we can see a gap appear as the shock absorber assembly is pulled down from the suspension turret now the nuts at the top have been undone:

9. We can see the shock absorber now bottomed out on the lower suspension arm:

10. Manoeuvre the shock assembly down and away from it’s upper mounting points like this:

Worth noting this job on both the rear and front on my car may be easier over OEM shocks / springs given it's already lowered so the shock with spring will be more compact. The only difference being with OEM you may need to use spring clamps at this point to compact the shock assembly just enough for removal.

11. Now pull the shock assembly clear and out like so:

At this point with another regular Billstein or similar shock with a lowering spring to go on you would have to transfer over the stock top mount which you can see in 7. is secured holding the unit together with one big nut. To do this you can do it the dodgy way by just undoing the big nut and watch as the whole lot pops off half way across your workshop or use spring clamps to unload the spring before undoing the big nut, taking the assembly apart in a controlled fashion for you to then transfer the stock top mount over to your new shock / spring combo to complete that unit and hold it together. Again, spring clamps are usually necessary to allow fitment of the stock top mount onto the shock / spring combo.

12. Onto the HSD Coilover setup. They come set to their minimum ride height and it’s easiest to set the ride height by putting them to their maximum ride height setting, mount them on the car then adjust the height downwards rather than trying to work upwards in height. To do this, remove the bottom mount by unscrewing it as so:

13. The instructions that come supplied state the bottom mount must be screwed onto the Coilover body thread by at least 20mm for safety so we measured 25mm to allow for the non threaded area at the very bottom, then screwed the bottom mount back on like this:

For future adjustment on car, some copper grease on the threads may be a good idea.

To set this ride height we then screw the locking collar into the bottom mount using the supplied C-spanner as so:

14. A comparison of a conventional ‘Coilover’ shock absorber assembly with the HSD Coilovers shows how much more compact a design aftermarket Coilovers tend to be:

This is somewhat deceiving as we’ll see later on – the higher spring rate and firmer damping means the aftermarket items don’t compress as much with the weight of the car on them and so the ride height can be higher with a shorter Coilover assembly total length.

15. We made notes of the measurements as they are at this point for later reference. First, the top mount to lower spring perch at 205mm:

Then the distance from the lower spring perch locking collar to the bottom mount locking collar (effectively the ride height setting) at 120mm:

Now the overall Coilover assembly length:

Don’t they look pretty?!?

16. Now we offer the prepared Coilover assembly up to the suspension turret mounting point:

The shorter assembly length makes it easier to manoeuvre into position than the old unit:

17. Now reach over into the boot and bolt the top into place to hold it captive:

18. Then jack the hub assembly up again to line the bolt holes up on the lower suspension arm and Coilover body and put the bolt back in along with the nut on the other end and tighten using the earlier described method:

19. After tightening the top mount nuts, the last job to do is fit the supplied adjusting knob for damping firmness (16-Step adjustment soft -> firm) by undoing the securing grommet slightly, then slide it onto the Coilover top and tighten the grommet using the Allen key supplied:

20. We noticed there was a slight gap because of the triangular rather than circular top mount design of the new Coilovers so used some common sealant to make it weather proof and insulate road noise:

21. Now to ensure the ride height is set by tightening the locking collar against the bottom mount using one of the supplied C-spanners:

22. Then the spring pre-load must be set as per the supplied instructions. The lower spring perch locking collar must be hand tight before fitment of the Coilover, then give the lower spring perch two complete rotations upwards and lock it in place. This eliminates any potential spring rattling also because you are effectively compressing it slightly. To measure the rotations, we marked the lower spring perch with tip-ex then rotated with one of the supplied C-spanners as so:

Then lock the lower spring perch in position by tightening the locking collar against it like this using the supplied C-spanners:

23. Now measure the spring length after setting the pre-load by measuring the distance from top perch to lower perch to allow you to set the other side to precisely the same setting. Same goes for the ride height setting by measuring the distance between the locking collars:

We can see this measurement is 192mm. After finding the ride height too high once the whole job was complete, we arrived at a locking collar to locking collar distance of 110mm to give my desired ride height of +10mm over my old setup. Anyone reading this should start with this setting with the Coilover off the car to save themselves a load of time over on car adjusting like we had to do .

24. The final job to do is use the supplied Wurth Ultra 2040 lubricant to lubricate the Coilover top mount bearing thoroughly:

25. Now onto the Front. Same process as before – get the car up, axle stand in place and wheel off to set about the job at hand:

Viewed from the front of car side of the hub, we can see it’s very similar in that it’s a bolt with a nut holding the shock to the hub assembly – just this time it’s more complex to remove the shock because you have the upper suspension wishbone in the way (the shock goes through the middle of it) and there is also the anti-roll bar drop link to be disconnected to allow the hub assembly to drop down enough to allow shock assembly removal.

26. First undo the bolt / nut securing the shock assembly to the suspension lower arm using the method as described earlier for the rear:

27. Now onto the fiddly, time-consuming part – disconnecting the anti-roll bar drop link. Toyota could have done a better job of designing these parts (same design on other Toyota’s of the era) – they are always a bugger to get undone because you have to stop the centre spline from rotating whilst undoing the nut. You are meant to do this using an Allen key in the end of the spline to hold it still whilst undoing the nut but in every case we’ve seen the Allen key hole just rounds off under the force and you need to resort to other means. This is where the locking long nose pliers come into play – grip the centre spline with them as tight as possible through the small gap between the anti-roll bar and the main part of the drop link then undo the nut as shown. Here's the way Toyota intend it to be done:

Here’s what you have to resort to if the locking long nose pliers don’t do the trick, a set of full on mole grips!:

Got the bugger with brute force and liberal application of WD40:

28. Now the shock assembly is ready to come away from the lower suspension arm, it’s time to undo the top mount nuts at the other end of the shock assembly. These are what you see under your bonnet:

29. Now use a lever to push the whole hub assembly down allowing you to pull the shock assembly down and out of the suspension turret mount:

Here you can see the angle required to remove the shock assembly:

30. Now manoeuvre the shock assembly like this to pull it out and clear:

31. A size comparison as per the rear:

32. Now set the ride height to maximum as described in 12. & 13. then wind them in further to make the overall length the same or shorter than the old unit you removed to allow refitment – it really is much tighter at the front so take note to save yourself time and effort:

33. Now fit the new Coilover assembly like so, again using the lever on the hub assembly to assist in getting it in place, then secure it initially using the top mount nuts under the bonnet:

34. Now refit the now copper greased bolt / nut to hold the Coilover assembly to the suspension lower arm and tighten using the same method as earlier. You may need to lever the hub downwards to line up the holes:

35. Again it’s very important to take measurements as you go to be able to set your ride height and pre-load and ensure it’s exactly the same at each side:

My target ride height was to get the front of the car +15mm over the old units. A final Coilover locking collar to locking collar distance of 40mm achieved this sensible but still low ride height – again take note if you want to save yourself a chunk of time by adjusting the Coilover to this ride height setting off the car as on car adjustment is much slower given the Coilover is compressed and not so easy to turn in-situ.

Don’t forget to set your spring pre-load as described in 22. & 23. earlier. The distance between top and lower spring perch should be 172mm on the fronts. Always tighten the locking collars to lock everything in place using the supplied C-spanners.

36. Then onto connecting the drop link back onto the anti-roll bar. Use your lever to line them up then the earlier method to lock the centre spline whilst you tighten the nut as shown:

37. Now fit the damping adjuster knob as described in 19. and then lubricate the top mount bearing with the supplied lubricant:

Look more toys! :

38. Here was my initial ride height on the front with the Coilovers at their maximum setting. I could have competed in the Paris -> Dakar Rally!!! :

The rear was far too high as well on max, but not quite as silly:

Using the figures I mentioned earlier in this guide will save you the absolute ages it took us to adjust to desired ride heights with the Coilovers on car. You also won’t go too far the other way on the fronts and end up with this:

Whoops!

39. To measure actual ride height of the car before and after, we measured the distance from the ground to the middle of the wheel arch through the centre of the wheel and from the centre of the wheel / hub to the middle of the wheel arch:

Measurements

Old height, Rear, ground -> centre of wheel arch – 660mm, centre of hub -> centre of wheel arch – 330mm

New height, Rear, ground -> centre of wheel arch – 670mm, centre of hub -> centre of wheel arch – 340mm

Difference - +10mm

Old height, Front, ground -> centre of wheel arch – 630mm, centre of hub -> centre of wheel arch – 320mm

New height, Front, ground -> centre of wheel arch – 645mm, centre of hub -> centre of wheel arch – 335mm

Difference - +15mm

This shows that my rear ride height is 25mm higher than the front and previously the difference was 30mm. Not sure how this compares with others? I’m open to guidance on a good differential front to rear and the approximate ride height setting for optimal handling. These were our best guesses!

Impressions:

These Coilovers are brilliant value for money! I’ve covered about 30 miles since fitting and so have them on their softest damping setting to let them settle (100 miles from fitting before adjusting from minimum damping is HSD’s recommendation). Like this, the car is noticeably stiffer but not uncomfortably so – it still soaks up bumps properly without any crashing or strange noises.

The car is now much nicer to throw down my local, poorly surfaced, potholed and frequently off cambered Scottish country backroads – I found the car now tramlines way less, has a much more eager turn in with minimal bodyroll and just seems to have more grip in general without getting upset going over road surface imperfections whilst pushing on. When I deliberately threw it too fast round a damp roundabout I found on the limit the car now has only slight but very controllable understeer. I also indulged in some ass out action and found the car surprisingly much easier to control – no sudden snap back it was prone to previously. There's also now the welcome elimination of arch rubbing, even with much increased cornering speeds so the combination of a slightly raised ride height and stiffer setup seems to have had the desired effect!

I need to have a full Geo setup done to make the most of my new suspension setup but I’m very impressed with the HSD HR’s already. You can tell they’re decent quality when fitting and adjusting them – everything feels nice and solid and does what it should do!

Total fitting time – 7hrs including an engine oil and filter change along with an auto trans interim fluid change. Then there was the time spent on taking pictures and messing around repeatedly adjusting ride height with the wheels on / off and car up and down in the air. Taking that into account, following this guide and not doing any other jobs should see it done in 5hrs tops. A huge thanks has to go to my Dad for his time and patience as always. Hopefully members can benefit from his work shown in this guide.

Total time spent on this guide – 6hrs 30mins . Enjoy!

Cheers,

Brian.

Very nice and detailed write up Brian

You had more patience with the drop links than TrickTT and I had when he changed my shocks, we knew they would be a pain so I bought new ones in advance and just cut the old ones off as soon as they started to give any grief.

It will be of interest to me and I dare say others if you could post up the Geo/Alignment printout after you get it done please mate

Very nice and detailed write up Brian

 

You had more patience with the drop links than TrickTT and I had when he changed my shocks, we knew they would be a pain so I bought new ones in advance and just cut the old ones off as soon as they started to give any grief.

 

It will be of interest to me and I dare say others if you could post up the Geo/Alignment printout after you get it done please mate

Thanks mate!

I'm too tight to buy new droplinks unless they're really really needed as per an MR2 I had where a couple of them ended up completely chewed up from the removal but the Supra ones were 'OK' in comparison. Lots of WD40 and swearing seemed to do the trick along with the locking pliers / mole grips.

Will likely get the 'lance' Geo settings from on here done - I know a good place in Edinburgh about 15 miles away from me that does an excellent job with a proper 4-wheel alignment rig with the mirrors and light beams etc. but can't remember getting a printout there previously so will check out my options hoping for a real Motorsports specialist place that won't be afraid to adjust the Coilovers if necessary to get things spot on!

Cheers,

Brian.

Great write up Brian, this should be made a sticky or added to tech references.

Great write up Brian

Great write up Brian, this should be made a sticky or added to tech references.

You never know, Ian could lob it into the ICE section as Spam!!!

Great Thread

Might be an idea for you to grease up the adustment threads, just a thin layer of Copper or Silver Grease, i did mine.

Ive had a few car's that have been fitted with coilvers and over the years they get really stiff due to corrosion, just a thought for you, saves you a bit of hassle in future

Have now added some detail to 10. & 11. around dealing with OEM suspension and transferring the stock top mount to another conventional shock / spring combo that doesn't come with it's own aftermarket top mount.

Cheers,

Brian.

Great Thread

 

Might be an idea for you to grease up the adustment threads, just a thin layer of Copper or Silver Grease, i did mine.

 

Ive had a few car's that have been fitted with coilvers and over the years they get really stiff due to corrosion, just a thought for you, saves you a bit of hassle in future

Good point actually and my Dad did say copper grease on the shock body threads especially around the bottom mount would be a good idea - we just used WD40 as we went but yeah future adjustment would no doubt be easier with the shock body threads having some grease on and I've noted this in the guide.

Cheers,

Brian.

Took some pics now it's clean to show what it's like with the new more sensible ride height:

Any comment on what the ride height should be for optimal handling on a MKIV?

Cheers,

Brian.

Copied into FAQ for prosperity.

Good read that I'm thinking of getting some BC racing coilovers for my 93 Mr2 Ride height looks perfect mate!

Awesome!!!

Thanks for that, I am planning to do mine and you have just made it 100% easier!

Fantastic write up Brian, I struggled in areas when we changed mine, that would have helped

Thanks guys

On the ride height, my thinking with respect the rear being slightly higher than the front is that when you accelerate the back end compresses so this means your car evens out rather than being nose up. Only thing is a standard Supra seems to have the front a good bit higher than the rear and I'm not sure what Toyota's reasoning was behind that?

Where's Toy Motor when we need him?!?

Cheers,

Brian.

Looks like a great guide but i can only see 3/4 of page 1 lol.

I'm guessing i'm out of memory?

Jeez that's a thorough thread. Well done.

I am not going try this myself. I'm going to follow SteveR and Wheels in Motion. Sheesh.

Looks like a great guide but i can only see 3/4 of page 1 lol.

 

I'm guessing i'm out of memory?

Not sure, it works fine for me with WinXP, IE7, 4GB RAM - there are 90 odd images though. Try a hold ctrl+refresh?

Thanks guys!

well done mate what a write up