Tuesday, April 14, 2009

Modernizing the DMC-12's Rear Suspension: Options, Resources, & Overview

I have nearly a complete set of parts and service history for 2109. Being a total geek, I spent a weekend afternoon once putting those in Excel. It was a worthwhile exercise because at a glance I can see what part (and if it) was replaced, and when. I am a strong believer in preventive maintenance (PM), so having quick access to that information assists me towards implementing PM on 2109.

Being a high mileage car (80K, relatively high for a DeLorean) means that it has been enjoyed by by its owners in the sense that it has been driven and not stored.  It also means that a lot of components have been changed, updated, or maintained. One of the most obvious components and service work that has not been performed, was on the suspension, she was still riding on 28 year old shocks and related components. I can’t complain, the ride is not bad, a little jolty on the occasional bump, but those old struts (non leaking by the way) must have seen better times. So, suspension work eventually made it to the top of the list of things to do, and I would start with the easiest, the rear.

I decided to attempt to do the rear suspension myself based on the fact that a) after research and speaking with others, that it didn’t seem too complicated, and b) I could save a few bucks from my budget and invest them in parts, rather than on labor. My backup plan as usual, if I get too over my head, I could always flatbed the car to DMC Florida.

Rear Suspension Work
Being on a budget also dictated that I had to buy the parts that I needed over a period of time, and not at once. So in approximately a 6-10 month period, I had all the parts that I needed to begin. Here are some notes, on some of the major components that I chose to use, and why:


With respect to the springs’ contributions to overall height, I actually do not mind my car’s stock rear height (picture above). The fronts, aesthetically yes, that needs to be lowered, but not the rear. This then simplified my choices as I would be reusing the existing springs.

Here is how the springs came out of the car:

Here is how they looked after some metal prep and several coats of satin black paint.

It took some work, but it turned out well enough that when another owner saw them, they thought that I had bought new ones.

Notes on springs thatlower the rear end:
Spring options for those that wish to lower their car’s rear height are: 1) use your front springs, in the rear, 2) use DMC’s Eibach’s lowered springs, or 3) cut your rear springs.

These are DMC's Eibach Performance Spring Kit:

If you do decide to lower the rear height, be aware that you must also replace your lower link, with an adjustable version, and have the wheels realigned for proper camber. If you lower your car’s rear stock height and you do not use an adjustable lower link, the camber of your rear tires will be off, and cannot be adjusted, which will result in the inside treads of your rear tires will quickly begin to show excessive wear.
This is what the adjustable rear links look like:

(Picture from midstatedmc.com)

These adjustable links are available directly from:
DMC Midwest
DeLorean Mid-State Club
DMC California
Pricing information varies per site, some require cores, some require your links to be sent in to be modified, Dave at DMC Midwest stocks them ready to ship. Reference individual links above, and contact them, for additional details.

Here we have quite a few choices. I'll list them in no particular order:


SpecialTAuto has two different kinds of shocks.
"Easy Riders" (Front & Rears as a set)

...and the "KYB Performance" shocks (front & rears sold seperately, rears shown below)

DMC sells a full set as part of their Eibach System (and actually NOS Girling ones too). They are sold as fronts and rears together.  Shown below is their full Eibach Performance System, but shocks and springs are sold seperately as well.  This is a popular configuration and nearly all installation reviews are favorable.

Marty Meier at Delorean Mid-State Club, has a front and rear set (with a lot of positive reviews posted).

Ed at DMC Europe has a unique set as well, part of his "Power Series", the "Power Shocks", which feature adjustable damping settings and polyurethane bushings built in.  Both front and rear shown below, but they can be purchased separately.

I have heard of a UK source for some shocks similar to Ed's, from the UK, and the shocks are brand: "Spax". If someone can email me public link, I would be glad to post pictures of them here, along with a reference link.

EDIT (05/11/09): I found the link, am fairly certain it is their "KSX" shock (picture from link below), but you'll have to call them for more details.

EDIT (05/17/09):
Chris Williams, the Secretary DeLorean Owners Club UK, has provided the further information and some detailed pictures of the SPAX shocks. He wrote:

"The well known company for performance shocks (SPAX) have agreed to start manufacturing shock absorbers (dampers) for our cars.  They are gas adjustable front and rear, with the rears being adjustable for the spring height on a S/Steel threaded outer tube. Fully Gas adjustable, with 28 settings on the adjusting knob. Spring height is also adjustable as you can see from the pictures.
Prices will be about, £74.99 each for the fronts and £99.99 each for the rear. There is 25% discount on these prices for DOC club members."
Rear SPAX in comparison to OEM. Take note of Stainless collar threads, AND a protective sleeve over the piston rod, two unique features of this shock absorber:

Close up of the bottom of the rear shocks, with the knob for the adjustable dampening settings:

I have to say that on features alone, this does appear to be a very interesting alternative, for replacing the rear shocks.
Edit: (05/26/09)
For more information on these, Chris says to contact Spax directly at: http://www.spax-suspension.co.uk/contact_us.php
If you tell them you are a DOC (DeLorean Owners Club) member, you get a 25% discount.  . . . Chris says that Spax does not call him to verify membership.   ; )

Edit: (02/22/10)
These shocks are now available domestically, exclusively through

Overview of which to get...
Which one to go with is honestly a leap of faith, and balanced by what are your driving expectations, and of course funding availability. Some are touted as “performance shocks” which give a stiffer ride, but hold tighter on aggressive turns and driving. Others are “touring shocks” which would mean a softer, cushier ride, which is not for everyone.

I drove a fellow D owner’s car with SpecialTAuto’s “Easy Riders” and I liked them, it was a soft ride on a less than great parking lot, and on a smooth open road at 50mph. I have heard others complain they are too soft, and in response John has released a stiffer 2nd option as shown above.

If you search you’ll find all sorts of opinions on installed solutions, but what is missing and we’ll probably never see, is a side by side comparison of multiple solutions, on the same vehicle. So really the best that could happen then to assist you on your choice, is to be able to have the opportunity to ride in as many cars as possible with the different shock and spring options, for you to evaluate personally, to make the best choice for your liking and needs.

For 2109...

I went with Ed’s Powershocks. They were not the cheapest, and the US to Euro exchange as well as shipping adds to the expense, but I decided on these because there had been some positive reviews on them, and the unique features that they have. They have a dial knob near the bottom, where you can dial the shocks to be set for either a soft or hard or anything in between. Chances are once you find your right setting you’ll never need to adjust it again, but who knows?
There are also two other feature which I liked about these shocks. One is that they have threaded collars, which seemed (and turned out to be) a very desirable feature to have to install and adjust them (height). The second is that the shocks themselves come with polyurethane bushings all around, as standard, which tends to balance the value of this option.

General Notes
That’s about all you need for to replace your rear suspension system. I won’t cover the installation details, as there are several sources that do so well enough, like a fellow owner’s “How To” on DMCtalk.com. I based my installation on that write up, and for the most part the suspension installation went well.  The job can get more challenging if you encounter"frozen" bolts and nuts. Fortunately I only had to deal with one stubborn frozen nut at the top of one of the shocks, but a nut cutter easily removed that obstacle. The other thing to check is the bushings on the links, if they are dry, rotted, or compressed, you may wish to consider replacing them, or even upgrading them with polyurethane versions (currently available at DMC-Europe, and in development at SpecialTAuto domestically).  Finally, the threaded collar on the shocks, mentioned above, did in fact make the installation easier, especially with this tool (found on Ebay).

Suspending the car on stands, and rotating the collar with this tool is a quick easy way to adjust the height of each shock..

In conclusion...
I have logged over 500 miles with my new rear suspension. Truth be told I believe the resulting effects are minor. I believe this to be the case because the full effect will not be reaped until both the front and rear suspension is upgraded.  Still the  rear suspension is now refurbished from the original factory components. The only issue that I have had has been a "squeek" sound from the shocks, but Ed advised me, and it has happened, that this goes away over time.

I could have left it at that, but instead I followed the “once you are there” philosophy, so I actually did some other rear suspension related work, mostly captured this (near) complete picture of the driver's side (LH) suspension:

What you can see, and what you cannot, that was done as part of the rear suspension work was:
 * Removed all the links to evaluate the bushings and to paint them.
 * Cleaned and painted the old springs.
 * Cleaned the parking brakes, and changed pads.
 * Replaced the worn parking brake cables.
 * Changed the rear flex brake lines with stainless versions.
 * Cleaned the exposed frame parts.
 * Cleaned off some road grime from the transmission.
 * Cleaned off the wheels
 * Removed, cleaned off, inner drive shafts
 * Replaced, outer drive shaft, bearings, and hubs.
 * Re-torqued all bushing related parts, and the trailing tab pivot bolts.
 * Cleaned off the interior of the wheels wells (not shown in picture).

Here is before and after shot of some of the visible parts and clean up work:

While most of those are details for another day, I would like to highlight a specific one mentioned above: "Replaced, outer drive shaft, bearings, and hubs."

Hub, bearing, and outer drive shaft
A secondary goal of this job was to repalce the rear bearings. I had the infamous "clunk" from the rear suspension when I got the car. It mysteriously went away one day and was replaced with a cyclic and surprisingly loud "squeek, squeek, squeek" on a turn. I figured it was the rear wheel bearings, that their time was up.

The wheel bearing is sandwhiched (machine pressed) between the outer hub and the carrier. To get it out requires a trip to the machines shop, to press it out, and to press it back in. Since I had to remove this assembly anyway, I figured I would clean it up and repaint it, but then it would mean two seperate trips to the machine shop, to take care of this. Also, the assembly is ulitimatly held together with a large 32mm nut, which needs to be tourqed to just over 260 ft-lbs.

I knew that I could tackle this, part by part, with some trips to a machine shop, and some brute strength, but I got an ideas to contact Josh B., at McFly MotorSports in Ohio. Although Josh's shop is relatively new to the DeLorean repair and restoration businesses, he is quickly gaining a great reputation for the service and quality work that he has put out, and some exciting engine performance upgrades that he has in the works (more info at this site).

Case in point, after contacting him, he sent me this picture of a recently restored hub/carrier assembly that he had worked on:

In this picture not only can you see the quality of the work on the hub/carrier and related suspension components,  but you can also see the quality of the restoration work of the frame that it is mounted on.

So, I engaged him to re-do my hubs, bearings, and outer shaft. Doing so all I did was to remove all three (carrier hub, bearing, outer drive shaft) as an assembly. This is what I sent:

...and this is what he sent back:

Given enough time, and having access to a media blaster, as well as two visits to a machine shop, some paint prep and paint time, I may have been able to achieve this quality of work by myself. However for what he charged, and how quickly he did it, it just made a lot of sense to have him perform this component restoration.

Contact him for more information:
Josh B.
McFly MotorSports

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