Jass Performance Top Mounts - Installation, before and after

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Jass Performance Top Mounts - Installation, before and after

Postby jass » Fri Nov 25, 2016 7:01 pm

Pre-story: The little cute 93 special I bought needed attention to the springs as of improper stand. Turned out to be fronts at the rear and the opposite.Changed them to some aftermarket (wont name them as they were sold and installed to me as such), which settled too low in a short time.
Now it was time to revert back to the amazing state of art S-Special yellow Bilstein with uprated springs suspension. Oh ... did I mention, I reverted back to the extremely, unbelievably lightweight OEM wheels with oem 185/60 tires from aftermarket 15s with 195 wheels?


Long story short - here starts the springs change.
To keep things easy and simple - you cant change springs without aligning the geometry afterwards. No point of keeping the suspension settings in this case. Easiest available option in this case is to loosen the front lower arms from the two adjustment bolts.
Of course it makes sense to mark and install them in the same way as to easy the way to the alignment garage, but the car will anyway drive differently with the different height springs.

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This is where we started from - car low down:
Front Image and back: Image

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As decided already, we are taking the easiest route - loosening the lower arm from the inside - the two adjustment bolts. Any other route involves more bolts and they are all more corroded or difficult to attach. Lets loosen them as first step.

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Next - lets loosen the two top (original 14mm) nuts as shown on the photo:

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Lets disconnect the strut brace link from the bottom bolt (14mm) and remove the nut from the shock bolt as well (17mm).

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Now comes a small trick to save some time decompressing the spring. Support the lower arm with the car jack and loosen the shock upper bolt - 17mm. The spring will expand and slowly lowering the jack you will end up with the spring detached from the shock in one step.

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The picture above shows the end result of the removed shock - the top hat, shock, seal, spring, nut and washer are separated. Compared are the OEM S Special spring and an aftermarket one here. Jass Performance Top Mount for comparison on the right here.

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The Jass Performance Top Mounts lower part - it centers the spring and even without the provided rubber cushions the spring wont bite the shock shaft.

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What we aim with this installation is:

-> lowest possible installation with OEM S-Special springs, best look respectively
-> still using the the cushions to support/center the springs
-> added shock travel

We have two options to install the Jass Performance Top Mounts - as with the OEM height, with lowered height or with raised height.
To install shock/springs in their previous OEM position the Jass Performance Top Mount cushions should be cut 16mm from the base.

In this case, we want to get car as low as possible with the OEM springs, so we are cutting the cushions as low as possible. The following pictures show the idea behind:

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The following pictures show the incompatibility of the OEM bump stops with the narrower diameter of the Jass Performance Top Mounts. The reasons for the diameter are actually the compatibility with the aftermarket springs diameters.

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There is obviously a part of the bump stops that needs to be trimmed as shown below. The picture shows the whole assembly put together - Jass Top Mounts + OEM bump stops + Jass Performance cushions.

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With this done the following procedure involves assembling the shock/spring/Jass mounts combo. Spring compressors are needed for this if OEM springs are needed (some aftermarket cold over springs are too short and can be installed without as of the low spring rate of the helper springs).
The rubber washer installs on the shock shaft before the washer. The whole is tightened ***well*** with the nut.

The assembly is installed back to the car:
-> easiest is to install the Jass Top Mounts at the top
-> connect the shock at the bottom
-> connect the strut brace link

The following picture shows the ride height with the Jass Performance Top Mounts, cut to minimum rubber cushions /potential to lowering available here if removed/ on a car with OEM Bilsteins and OEM S-Special 93 springs. One of the best suspension combination for the average British road.

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The front is ready and we can move to the rear. At took me approx. 30 min to remove the fronts and this much to reinstall - so an hour per front corner.

Rear of the car:
The rear is much easier than the front. As long as the upper two 14mm bolts are loose and the 17mm shock bolt is removed, with the strut brace loose (14mm bolt) the shock assembly can be taken out.

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The rest involves similar procedure to the front shock assemblies and reinstallation.

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Unfortunately the autumn days are shorter and detailed pictures of the whole rear installation process were not possible at this stage, but there is not much to surprise in the installation there as well.

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jass
 
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Re: Jass Performance Top Mounts - Installation, before and a

Postby Jorgens » Mon Dec 04, 2017 3:11 pm

How durable are those springs? Do you get most bang for the buck with those?
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Re: Jass Performance Top Mounts - Installation, before and a

Postby jass.performance » Thu Nov 15, 2018 11:14 am

The springs are the OEM springs that come with the Bilstein suspension for S Special Eunos Roadster.
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Re: Jass Performance Top Mounts - Installation, before and a

Postby Wardy » Mon Jun 24, 2019 12:52 pm

Looking to replace my top mounts, before fitting some Gaz suspension (type SI4231) to my S-Special. Would this be the 10mm version I need?

Thanks.
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