Suspension noise over speed bumps

[SonicHedgeHog]

When I go over a speed bump and the suspension compresses I get a kind of squeaky noise. Kind of like two pieces of wet rubber rubbing together. Had all the wheels balanced this month. Suspension, bushes all looked fine on the ramp although the suspension is old so the road grime could be hiding something. Does this sound like my shocks are on the way out? There is a speed hump next to the bus stop at work and old cars tend to make this noise but new ones don’t. Can’t help thinking it’s the shocks. Thoughts please?

[PositronicRay]

Check all the simple stuff 1st.

The last time I had a 'suspension' squeak it turned out to be a a bonnet catch in need of a blob of grease.

[Pica-Pica]

So the dampers ‘damp’? Press down hard and release - is a controlled restriction of vertical body movement?
Could be an anti-roll bar bush.

[SonicHedgeHog]

Everything works as it should and is fine the rest of the time. It’s just over big compressions I get this rubbing noise. Very difficult to describe. The anti roll car bushes are a good shout actually. It’s going in for an MOT and an oil change in a month so I’ll get my man to take a close look at everything. Its not the suspension bushes because they were changed about 20,000 miles ago for OEM items and the chap at the wheel balancing centre agreed that everything looked in good order.

[E-bmw]

My best guess would be strut tops, but it could be one of many things.

[SonicHedgeHog]

E-bmw said:

My best guess would be strut tops, but it could be one of many things.

Strutt tops are A1 inside the engine bay. This car is family owned from new and has wanted for nothing. It’s a Subaru Outback and built to last. I’m sure anything that’s wrong is a ‘consumable item’ and not the car wearing out.

[Smint]

I'm into annual rustproofing (trying to make our Subaru and Prado last us out), give both vehicles a good wash down underneath after winter to remove the salt and reapply a good covering all over and inside the necessary in ACF50 (plenty of other choices), not only does good rusproofing prevent corrosion it shuts up most squeaks and groans from dry bushes etc.

[SonicHedgeHog]

Thanks for the tip. I’ll bear it in mind after it’s been up on the lift and we can have a good look at all the rubber bits.

[SonicHedgeHog]

Following further experimentation I reckon the problem is the isolator rubbers at the top of the suspension. If life depended on it I’d do the job myself but I don’t fancy crawling around on the floor changing all four corners so I’ll give the job to my tame mechanic. With this in mind I have another question(s).

1. My car has done 180k on its original suspension. I plan to keep it another 50 years so I would get value out of changing the suspension. Do you think I will see a big difference in changing my apparently fully operational suspension given how many miles it’s done?

2. Do you think it is worth changing the suspension when I get the isolator rubbers changed as it appears to be much the same amount of work whether I use new or old suspension?

I hope you can see I’m trying to get maximum value out of my mechanic and would like to avoid paying for almost the same job twice. Cheers.

[E-bmw]

SonicHedgeHog said:

E-bmw said:

My best guess would be strut tops, but it could be one of many things.

Strutt tops are A1 inside the engine bay. This car is family owned from new and has wanted for nothing. It’s a Subaru Outback and built to last. I’m sure anything that’s wrong is a ‘consumable item’ and not the car wearing out.

So it was the strut tops after all.

[SonicHedgeHog]

Don’t know mate. Everything I can see is in A1 condition. However, through a process of elimination, continual monitoring and an acceptance that I can only see part of the rubber I reckon it probably is. Reading back through the thread I misunderstood what you meant by strutt tops. I thought you mean the metal bits rather than the rubber.

[E-bmw]

Generically I would replace the whole thing but the rubbers are quite often what makes a creaking/squeaking noise.

[SonicHedgeHog]

So what’s the feeling about the shocks and springs? OEM items are about £500 for a set of four. I shall head over to the Legacy forum to ask about upgrades but I’m kind of thinking change the lot to minimise the long term labour cost. What do you think?

[E-bmw]

On most cars the tops can be swapped safely without spring compressors by lifting the corner on a stand then jacking the strut back up then undoing & reversing the process to refit, an extra pair of eyes/hands helps.

It is a simple enough job with the right tools.

I wouldn't do the full strut unless there is reason to worry about longevity.

[SonicHedgeHog]

Didn’t know that, thanks. I’ve got 500 miles to drive tomorrow over varied roads. I’ll see how it goes. Over moderate speed, uneven roads it can get a bit floaty. Not an urgent problem but might be a sign that the dampers are past their best. Cheers