Effects of broken AGX bumpstops?

[HokieDSM]

Just a quick question here-

In my fiddling with the new wheels/tires (see other threads in this forum) - I've noticed that the bumpstops on my AGXs look to have broken and parts of them have slid down the shock or resting on the springs. What would be the negative effects here, and would it be cruicial to replace them? Should I use OEM bumpstops or should I get another set of AGX stops?

 

[Ralli///Art GS]

http://www.hrsprings.com/site/frametechnical.html

Found this article you should check out, click on the Micro Cellular Jounce Bumper link when you open that page.

 

[HokieDSM]

Good read, but it didn't answer my questions.

 

[tanner261]

The bump stops prevent metal to metal contact between the suspension components. Yes you need them. Without them your car will get really lose in a corner if the suspension bottoms out. I'm not sure if KYB makes bumpstops, most likely the ones on your car are OEM. When I replaced my stock struts 4 years ago, the front bump stops were toast and had to be replaced with OEM units. They aren't too expensive from the dealer.

Make sure you don't run full height bumpstops with lowered suspension, they need to be cut to retain suspension travel.

 

[awd4g63]

Eventually, your shocks will end up piercing through the top of your strut tower. Replace those bump stops. If those are bad, I wonder how your bushings look?

 

[3literpwr]

Eventually, your shocks will end up piercing through the top of your strut tower. Replace those bump stops. If those are bad, I wonder how your bushings look?

Your shocks wont pop through your shock towers but you can blow the base valve out of the shock.... The base valve controls the compression force in a twin tube damper.....

This is why so many guys that get coilovers sleeves shocks go bad so quick as many of them remove the jounce bumpers.....

They are importans and a tuning tool!!

Larry
#622 SCCA CLUB RALLY
Shock design, tuning and other rally and motorsport services........

 

[awd4g63]

Your shocks wont pop through your shock towers

I know, I was just being a little sarcastic

 

[HokieDSM]

The reason I asked if they were OEM or KYB was because they are yellow - to give an idea, this is what I'm looking at - they look like this pretty much on both sides...

 

[3literpwr]

It looks like the bumper is on the OD of the shock body so its not doing a thing.....
you can get stock type bumpers or some out of a racer catalog..... True choice sells them along with many other companys......

Funny thing I saw some JACK ASS on tuner transformasion CUT some jounce bumpers last night!! I was shocked that they would do that on TV!! I guess there suspension guy is not to bright..... :thumbdown

Larry #622 scca club rally

 

[tanner261]

Stockers are yellow.

3litrpwr, do you suggest not cutting the stock 'jounce bumpers'? The instructions for my H&R springs suggest to cut 1" from all 4 corners.

 

[steve]

Most lowering springs require you to shorten the bump stop about the same length as the springs lower the car. My Pro Kit had you remove an inch.

 

[HokieDSM]

Dammit - I just waited a week for an order from Conicelli to come in, looks like I'm gonna have to make another one.

As far as ordering the part goes - would it be the part #7 - which Conicelli labels as "DUST SHIELD"? How much of a PITA will it be to replace them?

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[98TsiAWD]

Nope, thats the dust shield. Hold on a minute, Im gonna go search for a conicelli reciept from when I got bump stops.

Ok I found it, here is the part number: MB949043, They are $4.52 each. Thats listed as a Damper, RR Shock A. But I know thats the bump stops.

If you need new dust shields here is the number for those:
Front: MB864911
Rear: MB864787

 

[HokieDSM]

Thanks - just for the sake of my own curiosity, which # would they be represented by on the diagram above?

 

[3literpwr]

I am extreamly suprised that your directions with your springs said to do that??!!! I supose if they put ALOT of spring rate in them buggers you wont be on the bump stops but They are a saftey measure and a tuning aid.... Having a slighty longer jounce bumper wont hurt you, but having one too short certainly can..... Base valves in twin tube shocks can be destroyed quick from metal to metal contact..... I would rather have a rising spring rate from from a jounce bumper than a blown damper from that pot hole or curb you hit....

Larry

 

[steve]

Thanks - just for the sake of my own curiosity, which # would they be represented by on the diagram above?

It's the unnumbered part between 7 and 8.

Steve

 

[tanner261]

The directions were straight from H&R, which is the same people who wrote the article on the jounce springs.

 

[HokieDSM]

I checked on Conicelli's site for the bumpstops - and the partnumber posted above for the bumpstop seems to be for the 2G.

Using CAPS - I was able to dig up the part number for the 1G, which seems to be MB349347 - written in CAPS as "DAMPER, FR SUSP, STRUT" - and as a "Damper" or "Strut Bumper" but is NOT listed when browsing the 1G mechanical or collision catalog - although it is listed for the 89-93 Galant and for the 3G Eclipse/Galant.

The listed price is $10.87 - 1G stuff seems to always be more expensive :thumbdown

 

[HokieDSM]

Speaking of directions - I'm ordering the bumpstops now; can anyone verify that the directions for the Eibach Prokits specify to cut the bumpstops? My set came with the car, so I don't have the directions.

 

[jtmcinder]

I am extreamly suprised that your directions with your springs said to do that??!!! I supose if they put ALOT of spring rate in them buggers you wont be on the bump stops but They are a saftey measure and a tuning aid.... Having a slighty longer jounce bumper wont hurt you, but having one too short certainly can..... Base valves in twin tube shocks can be destroyed quick from metal to metal contact..... I would rather have a rising spring rate from from a jounce bumper than a blown damper from that pot hole or curb you hit....

How many shocks can actually have the piston hit the base valve (aka foot valve, if you have Konis) if the shock is installed correctly? In other words, when you compress the shock until the collar on the shaft is right on top of the shock's body, for how many shocks does this cause the piston to be in contact with the base valve?

Assuming that some (or all) OTS shocks for DSMs do have the piston hit the base valve at full compression, by how much would you have to extend the shaft to avoid this? Is the amount of extension required equal to the whole (compressed) OEM bumpstop? Two thirds of it? Half? One third?

Without definitive answers to these questions, you are not in a position to give advice that goes against the suggestions of Eibach, H&R, and Ground Control, among others. I don't know the answers (either), but I know that my foot valves are fine after three years with one third of my bumpstops removed.

- Jtoby

 

[HokieDSM]

One quick question - looking at the original pic I posted above, that IS the bumpstop, isn't it? I don't want to go about ordering the wrong parts.... I ask because looking at this tech article that doesn't look anything like what's in the pic above... (and it mentions KYB specific bumpstops - whereas I ordered OEM)

 

[jtmcinder]

I'm not sure. My first reaction when I saw the picture was that it was an ES shock bushing (and that the washer-looking thing underneath it was the washer that is supposed to sit on the collar on the shock shaft), but that would be a serious problem and I'm not sure if you could even be driving around if it is. Do AGXs come with reddish bumpstops? Are the color maps on my monitor off? It sure looks more red than OEM yellow to me.

- J "color-blind and trying to deny it" toby

 

[3literpwr]

All Twin tube dampers can hit the BV's unless restricted... Either by using a bump stop or coil bind..... Jt you may have plent of pring rate to keep you off the bottom of the damper then again you may reach coil bind first I dunno.... I really dont care much about DSM's I just happen to rally one..... I just have built tons of shocks and know a thing or two about them..................

How much can be cut off is a unknow amount and is only relevent to that one shock type/brand.............

The important thing is that its not a great idea to cut jounce bumpers into little pucks! Keep in mind that most peoples bumpers are old and WAAAYYY softer than stock....


Cheers
Larry

 

[Ralli///Art GS]

I went to the dealer the other day since I just got my new AGX's in. They wanted 109.00 for 4 jounce bumpers and 4 shock boots (found this out after I had to explain what they were to the parts guy for 15 minutes). Check out TireRack.com and you can get the KYB shock boot/jounce bumper combo. I ordered 4 and it came to about 56.00 shipped. I'll post after I get them install in this weekend.

 

[HokieDSM]

I went to the dealer the other day since I just got my new AGX's in. They wanted 109.00 for 4 jounce bumpers and 4 shock boots (found this out after I had to explain what they were to the parts guy for 15 minutes). Check out TireRack.com and you can get the KYB shock boot/jounce bumper combo. I ordered 4 and it came to about 56.00 shipped. I'll post after I get them install in this weekend.

Those prices seem way high from the dealer, and even high on Tire Rack. Like I posted above, from Conicelli, OEM jounce bumpers were $10 each - I ordered two and they should be in tomorrow, I paid less than $25 shipped for both.