I am looking at getting the rear shocks and springs replaced when the shop is going to replace the rear bushings on my 244.
The rear bushings are going to be the IPD polyurethane kit. For the shocks, can anyone comment on the difference between the Bilstein B4 (Touring/black color shocks) vs. B6 (HD/yellow color shocks)?

Does the B6 worth the money given that my 240 is a Sunday driver only for 6 months in a year.
For the springs, I am thinking about buying the Moog CC215 or AC Delco 45H3054? Any preference among these?

 

Unless the ride height is too low, I'd leave the springs alone. The shocks in the back take a lot less pounding than the strut on the front, so something basic would do.

 

Thanks!

 

As far as the springs, I believe the Delco's are made by Moog. They basically have the same initial load rate as stock springs but they're progressive, so the rate increases as you carry more weight. If you don't plan on carrying a lot of cargo I'd stay with the stock ones. The Bilstein B4's are twin tube gas shocks and slightly stiffer than stock. The B6's are heavy duty shocks and take twice as much force to compress as the B4's. They will give you a very stiff ride. Stay with the B4's or even Monroe's which are a decent shock, smooth ride and a lot cheaper.

 

I appreciate the valuable information. Few more questions that I couldn't find clear answers on:
1. Shocks -> Any preference on the KYB Gas A Just vs. the Bilstein B4s. The KYBs and B4s both come with lifetime warranty. However, KYB has rebates going on. For now, I am dropping the B6 from my list.
2. Springs -> Stock springs are saggy. I can compress them easily with my hands. Would switching to the springs out of a wagon help? The cost is about the same. Keep in mind, that I won't be doing front struts until next year.

The sedan's spring rate is 107lbs/inch and the wagon is at 155lbs/inch.
Sedan springs: https://www.rockauto.com/en/moreinfo...287053&jsn=849
Wagon Springs: https://www.rockauto.com/en/moreinfo...287053&jsn=850

Given the higher spring rate and the thicker bar for the wagon's springs, should I buy them instead?

The poly bushing kit from IPD is on order!

 

every pair of KYB's I've ever put on most any sort of car lasted a couple years then went bouncy, with low damping.

stiffer 'sport' shocks should be matched to stiffer springs

I dunno if today's replacements are the same quality, but the Boge-Sachs shocks that were the OEM spec lasted the longest of anything, and were perfectly matched to the stock spring rates.

 

Yes, it seems like the OEM struts and shocks last the longest. The problem is that people don't want to pay that kind of money so they buy something that gets them by. for that reason, I don't change them unless they are leaking or in some other way faulty.

 

My shocks have been done for the past year and they are certainly due for replacement. The OEM parts are a little too expensive for the amount of miles I put on the car.
Bilstein HDs might be an overkill. The Sachs/Boge looks to have mediocre reviews after they switched to manufacturing in Mexico over the past couple of years.

So it boils down to Bilstein B4 vs. KYB Gas A Just. Are the B4s longer lasting? I saw a bunch of issues with the B4s knocking/rattling from older threads. Have these been fixed?

 

You're right about Sachs. The Mexican made vs the German leave a lot to be desired as far as quality. And Sachs no longer makes the Advantage which was their twin tube, gas strut insert, the same strut that came standard on 240 and 740/940 Turbos. The one they make now in Mexico is a twin tube oil strut, not gas. And you can get it in a rear shock also. Strangely though, they still offer the Advantage in a gas, rear shock, but it's mono tube and stiffer. The KYB Gas A Just is their version of a mono tube gas shock, basically a performance shock, and again a stiffer ride. If you wanna go KYB and closer to OE go with their GR-2/Excel, it's their twin tube model. General rule: gas is stiffer than oil, mono tube is stiffer than twin tube. I would consider the Monroes. Their quality has improved. In fact, Volvo outsources them for some of their later models. US made and lifetime warranty. As far as springs, I wouldn't go with the wagon springs on a sedan, unless you we're going to carry a bunch of people or go racing on the weekends. The nice thing about the Moog cc215's are that they're progressive. The initial load rate is the same as stock but as the rear weight increases so does the load rate. I put them on my 940 wagon and it was a nice combination of ride and load carrying if I needed it.

 

That's a bunch of good stuff. I will buy the Moog CC215 springs and the Bilstein Tourings/B4.

I am certainly looking for a slightly stiffer set up than OE, which is how I ended up looking at the Gas A Just. The GR-2/Excel's seem to have negative rep on other forums for different manufacturers. I have used the GR-2 on a Subaru before and it seemed to be sprung too softly/mushy. Pierce didn't seem to be confident with anything under the KYB umbrella.....so decision made!

Interestingly, IPD and FCP both recommended either Bilstein or Sachs over the KYB Gas A Justs when I called them up.