Hitting suspension stop Fixed 30-3-2022

[Rinke]

Hi Guys,

I've upgraded my 175/70R13 tyres to 185/80R13's, but now my suspension hits the stop more often.
Could this be due to the larger tyre size, or should I start looking at the suspension.
It happens with both front and rear stops. On the PS both my stps are damaged from one particulary nasty bump with a heavy load (I absolutely hate speedbumps that still launch you when going BELOW the designated speed limit).

I've done the wobble test with the shocks, I can get the body to start hobbling quite easilly when pusing one corner, but it stabilises after one or two wobbles after I let go.
I had her road safety tested recently and asked about the suspension, and the mechanic (experienced in older cars) said it looked fine.

I've done some reading and (correct me if I'm wrong) the shocks seem to play a role also in ride hight. Not only stabilising the car.
It was mentioned on a few forums when I was searching the internet.

For your information:
The rear springs where professionally refurbised during the resto, and are approx 13 years on the car now, about 70-80K km's on the car since the restoration.
The front springs I assume are original maybe 200K on them atm since 1963

The shocks all round were good when I restored the car, so I reused them, probably early seventies.
I think there is some sweating on one of the front shocks, but if it was severe it would have been a fail point for the road safety test.

Thoughts??
I'm hoping it is not the springs, I'd hate replacing the front coils, scares the shit out of me compressing them.

Greetz Rinke

 

[bubba22349]

Hi Renke, I think at the minimum you will at least need some new shocks, when you test them just push down on a corner then let it loose again if it bounces up and down then that shock is weak and needs to be replaced. A good shock after you push down comes right back up to the top and then stops there shouldn't be any rebounding after that. The right type shocks can really help with a cars handling.

The only types shocks that can have any effect on the cars Suspension or Ride Height is a Coil Over, an overload shock that also has a coil spring mounted around it on the out side. or the air type overload shocks these are somtimes used on the rear axle of a Ranchero or Station Wagon that needs to carry some extra weight to rasie up the rear when carrying a load. Is the car leaning any when setting on level ground? Is there signs of the car setting lower than its was stock? Those destroyed bump stops on the passenger side might indecate a weak or staging spring or springs on that side. Best of luck

 

[B RON CO]

Hi, X2 on new shocks. What air pressure do you run in your tires? I would try 28psi. Too much tire pressure will give you a stiffer ride. Good luck

 

[Rinke]

Thanks for the replies.

When in rest the car sits level.
When loaded she lists slight to the PS side (two people sitting there and the spare)

I checked the tyre pressure, I'm running 2.5 bar, that should be somewhere around 38psi, but I was adbvsed to use the higher pressure by the tyre company.
I'll try and lower the pressure in the front. It defenitely is related to the larger tyres, but I'm researching new shocks as well, the are +20 years old

 

[sixtseventwo4d]

That's a remarkably high pressure recommendation. Tyre manufactures are going to recommend higher pressure that give longer life and fuel economy, almost nothing toward ride comfort.

Almost any replacement shock will give good rebound control . What you will be looking for is one that offers controlled compression resistance as well, which will be something found in a mid-grade shock or better

 

[bubba22349]

Thanks for the replies.

When in rest the car sits level.
When loaded she lists slight to the PS side (two people sitting there and the spare)

I checked the tyre pressure, I'm running 2.5 bar, that should be somewhere around 38psi, but I was adbvsed to use the higher pressure by the tyre company.
I'll try and lower the pressure in the front. It defenitely is related to the larger tyres, but I'm researching new shocks as well, the are +20 years old

That doesn't seem like much of a load only having two people and a spare tire on the PS I doubt this add's up to 400 pounds of a weight load, if the suspention moves it shouldn't be very much. Did you measure the empty height and loaded height to see how much difference there was? If not take a measurement at the center of the front fenders wheel opening and then at the rear for a good compareision of the empty and loaded weights. It is Interesting that the suspension moves so what if you switch that same PS load (of two people and the spare) over to the DS side than what do you see happening? Yes X2 that does seem like a bit high on tire pressure over the stock recommended tire pressures It won't help the suspension problems your having though if you lower the amount of tire pressure. Best of luck

 

[Wesman07]

When your tire hit a bump such as a pot hole it creates a very fast upward wheel speed. On cars it can be as high as 60in/sec. Spring don’t slow down these speeds very well, they are better at holding the vehicle up. For this reason shocks damp compression movements. It’s very possible the shock performance is starting to fade.

The other possibility is the tires have a stiffer side wall or are set at a higher psi than the original set. Both cases will create a faster upward wheel speed that the shocks have to slow down before the bump stops are engaged. The reason for this is the tire will absorb less of the bump making the bump feel taller and sharper then it needs to be.

Tire pressure is mainly determined by vehicle weight and speed. If the tire has too much of a sidewall bulge it will get hot and delaminate causing a blow out, speed is also a big factor in sidewall heat.

Moral of the story, always go with the vehicle manufacturer tire pressure recommendation and stick with the same sidewall rating. It is your safest bet.

 

[Rinke]

In hindsight I was experiencing buper stop hits with my old tyres, but not so often. I was running them with higher psi as well.

I'll order a set of new shocks. I finally managed to get a new garage, so I can turn wrench again. (it's rather frowned upon if you do that on the sidewalk here).

Thanks for all the replies. I'll post back after installing new shocks.

 

[Rinke]

Hi Guys.
I need some help with deciding on shock type.
My ocd is getting in the way and i do not intend to spend the next 4 years pondering on shocks. (Like i did for my tyres 😅).
I'm eyballing either Monroes or kyb's.
I'll have tot order them on line anyway because falcon compatibele shocks are hard to come by here.
I'm leaning towards the kyb gas adjust setup. I can order that thru summit.
Are there serious issues of adcantages with using the gas adjust or should i go for the non gas adjust from either Monroe or kyb?

The goal is a maybe a little stiffer ride but nothing wild. The car is stock and Will remains as much as possible so.

Greetz Rinke

 

[Wesman07]

Greetz,

I have always been a fan of KYB. They just make good stuff. Mono shocks are also more performance oriented in that they can handle more demand. Also, because mono shocks are filled to a higher gas pressure they help the car stay up off the bump stops.

 

[wme013]

2x on KYB. Bilstein's the very best, IF they make one for your car and IF you can afford them

 

[Rinke]

Wesman and wme.

Thanks for the response 👍

Kyb seems to be the way to go!

Greetz Rinke

 

[Rinke]

Hi all,

Finally managed to install the shocks and take a testdrive.
I ended up with KYB gas adjusts.
Ordered thru summit and got them within a week. I was impressed.

After removing the old shocks, (thank god that I used copper grease upon assembly) I installed the rears first (reasoning those were only 2 nuts each), but due to the gas charge I needed to compress the shocks and tie them with metal wire. On the PS that worked, the DS gave me more trouble, but I could fit the extended shock onto the lower mounting point (on the other side the exhaust was in the way) and compress the shock whilst laying down. Installing them took the better part of the afternoon. The frons were more nuts, but the PS was fairly easy, with the car raised a bit the shock only needed minor compression and installing it was easy. Once again the DS gave me troubles, the upper mounting was easy, but my thickfingerness was an issue with one of the lower bolts, after copious amounts of sweat and some foul language the job was done (this last nut toook about 2 hours to get sorted....).
I forgot to meaure the rear before and after and from the front I only thought about it at the DS.
Basically before it was approc 67cm, from underside fender to the ground and 35 cm from underside fender to venter hubcap.
After the measurements were the same.

The rear is raised a little bit, but it actually looks good/better than with the old shocks.

The old shocks were totally gone. Extension had some resistance, but on all 4 I could hear bubbling noises coming from the shock. Compression was on most without much resistance and on the DS front there was actually a free travel of about 5 cm/2 inches.

On sunday I took a test drive with the family of about 200 kilometres.
The car handles very different in a positive sense.
Suspention is much stiffer, but still comfortable. With the girls sitting both one one side the car still lists slightly, but less than before. I misjudged some speedbumps and the car went over them without hitting the stops, with the old shocks this would have been the case.

Overall impression on the new shocks:
- the car is raised slightly, but not annoying/diproportional
- driving caracteristics are changed in a positive sense. The car feels more secure on the road
- installation was fairly easy (on garage floor with basic jack and jackstands)
- the amount of muscle needed to install the shocks was more then anticipated, but manageble (I'm 46, 6'6" and used to heavy work) but I can see if you are older/have less physical strength it can be challenging

So all in all I'm calling this issue fixed!

Thanks for your input!

Greetz, Rinke