P38 4.6 Shock Absorber mistake?

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P3846HSE

P3846HSE

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Hi Folks,

Not new to following forums but first time I've become involved; recent purchase of a P38 maybe the reason to get stuck in.

Im interested to know if anyone has any input/first hand knowledge on an issue I've encountered regarding the ride quality in my P38.

To paint a picture:

-Purchased 1997 4.6 HSE GEMS car this September with 127,000 miles - also has the correct 18" Mondial wheels with "lower profile" tires which might become relevant
-Running on original air bags and shocks
-EAS compressor running a bit more than I believe it should
-Replaced all air bags with new Dunlop units - the originals were heavily perished but still holding air overnight
-Replaced original shocks with Terrafirma Heavy Duty shocks (ones that retail for circa 140.00 for the set)
-The result is that the ride is now appalling. I have a Series 1 on original leaf springs and its not that far off that now to give an idea - only slightly tongue-in-cheek

Whilst mechanically sympathetic and having a relatively OK knowledge of whats going on underneath the P38 I am hoping that the gas filled Terrfirmas were just a mistake - too hard - and a move back to original, soft, lazy shocks will bring back the lovely ride perhaps?

I am not interested in handling and not fussed by body roll. Could anyone comment on what they think may be the issue here and also the ultimate sponge pudding shock I can put back in?

Many thanks in advance.
 
I would suspect the shocks.
If you've still got them refit the old ones & see what happens.
If the ride is now much nicer then you have your answer.
(I once tried very heavy duty springs on the rear of my coil sprung RRC, fantastic when fully loaded & towing but would have your fillings out empty!)
 
TF shocks are ShíT to put it mildly if they're the blue Heavy duty ones means you cannot go offroad or lift the car by the chassis as the bags will pull apart, as the shocks are +2 inch and the shocker is what limits the axle articulation..

they're made to be stiffer!

Put it on a set of BOGE OE shocks if you can find a set, or some Monroe's and as a final resort Britpart Cellular dynamics, which are actually quite good.
 
Yep to hard a shocker will do it, i have adjustable shocks on my classic car and made the mistake of putting them to hard and it would wheel spin and jump and bounce all over the shop turned um down straight away much much better:)
you live and learn:D
 
Thank you folks - that's a pretty sound conclusion that I've fouled it up with these shocks, and I think makes perfect sense. Managed to find a set of Boge fronts and I'll keep digging for rears Henry_b, believe this is the right direction. Thanks for the feedback all, will let you know the results once I've spent a day out in the garage. Cheers.
 
The fronts are longer than the rears, what did you do with the cups on the the bottom of the shocks? Not easy to get in properly some choose to leave one off.
Can’t speak for EAS but I don’t find TF particularly uncomfortable in any way but they are in no way the quality of Boge units. I have the black HD ones
 

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There is a set way the washers need to be, i believe they should be like this dish together )( and not like this ()
 
Thanks brianp38dse, yes I see your point re. the washers. Logic would suggest the 'male' side of the bush sit inside the chassis cups and the washers sit inside the 'female' part of the bush as such )) axle ((. This is what Ive done but that also looks like there will then be zero give in the solid rubber bush, thats what it feels like at least. Alas, I think my problem goes beyond this.

RangeRollerdt - yup so Im still on air, and have arranged the washers and bushes as above. Might well have a look at trying a different configuration.

General feedback. The feel when driving is one of two possibilities I think:

1 - the TF shocks are too long and too stiff and are negating the air bags as the bags are simply not being 'used' properly. Ie. the car is riding on its shocks.

or

2 - it feels like the bags are in High mode when driving, although the dash toggle reads Standard height and a visual inspection suggests they are in Standard mode, albeit a touch high

Any input welcome!

MIGHT ADD: new shocks not arrived yet so probably better I respond when Ive swapped them out.
 
Last edited:
What size are the tyres? I know you said they are lower profile. If they are like rubber bands they wont be helping
 
Kev12 said:
What size are the tyres? I know you said they are lower profile. If they are like rubber bands they wont be helping
Click to expand...

I agree - they're Cooper Zeon 255-55-R18, also XL with harder walls..and they're over-inflated. Recommended pressures Ive seen on various sites is 28 front and 32 rear. Mine are sitting at around 40 having checked last night. Probably explains a lot too!
 
kermit_rr said:
Why did you go for HD shocks? Have you checked they all function as intended with full travel in both directions?
Click to expand...

Poor research on my part, I was unaware that they're more appropriate for lifts and off road work. Entirely my fault and a poor decision! Yup, so they do travel correctly in both directions but there is significatnly more resistance than the originals I removed. Again, I should have seen it coming!
 
The way to tell is measure with a tape the heights (centre of wheel to arch on flat ground) and compare to what they should be here
0E96BCFB-7F8D-45F2-8949-2060DD47E606.jpeg
If the shocks are too long your readings will be also. If it is as you think and are riding on the shocks more than airsprings they won’t last long, likely snap at the bottom
 
RangeRoller dt said:
The way to tell is measure with a tape the heights (centre of wheel to arch on flat ground) and compare to what they should be here
View attachment 225753 If the shocks are too long your readings will be also. If it is as you think and are riding on the shocks more than airsprings they won’t last long, likely snap at the bottom
Click to expand...


Thanks - yeah I have used this image to measure last weekend. All designated heights were about right other than Standard which was 10-15mm higher than it should be all round. I'll be swapping the shocks out the moment the frsh ones arrive with very little driving inbetween - noted that the shocks could shear.
 
Pleased to report that the return to Boge has remedied the situation. Thanks to all for their input and advice, very pleased to have joined in to get some thoughts and opinions. Between a relatively lengthy process of getting the original air springs out and new ones in, correct shocks now and relevant bushes replaced we're in a good place suspension-wise. Cheers.
 
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