68sting

I'm having a heck of time with vbp fiberglass springs. It's a 360lb spring. I looked under the car one day and noticed it was breaking apart. I ordered another one to replace it and talked with the someone at vbp about it. Never really got an answer on why it broke. Well here I am again with a broken spring. I'm leery to order another one. Does anyone else have this issue? Any ideas on what would do this? I would guess this spring doesn't have 20 miles on it in the last 5 years.

MN80Vette

I've had the spring on my '80 for years with no problems. Did you use blocks of wood on the spring when you clamped it? Metal clamps on the fiberglass spring would stress a very small area. It has been a while, but I remember warnings in the directions about clamping directly on the spring.

I see by your traction bar you have some large speedbumps in your area. I'm glad I made my traction bar with a profile about half that of yours and more clearance.

68sting

I followed the instruction on install. No damage there. I'm at a loss here and I don't know what to do. Nobody else has had this issue?

Gordonm

There have been a few broken springs here on the forum but the majority of them do not break. Something seems wrong here if you are breaking so many so quickly. I would call VB and explain the situation. They have been very helpful to me in the past. I have had probably 4 different VB fiberglass springs under mine and never had this issue.

69schemers

How close does your exhaust run to them? I have heard of people damaging the spring due to the exhaust being to close. By the looks of your muffler, you already removed the pipe?

WESCH

Hi

There where a couple of threads where the dual mount rear plastic spring broke. You might find them back in the surge function.

I don't remember if they mentioned a reason for failure.

The way yours is broken looks like a twist break. But how could the spring be twisted at the ends ?

Rgds. Günther

MN80Vette

Now that schemers mentions it, I don't see a heat guard on your spring. Do you have side pipes? If so, heat guards are not a factor. If not, then heat could be a factor.

Grumpy 427

Will header wrap on the pipes say a foot on either side of the spring be sufficient? Thats what i plan to do with mine.

68sting

The exhaust is off in the picture but it is wrapped with header wrap near the spring. I would think the labels on the spring would show signs of heat damage if that was the case.

LIQUIDDRAGON

I would say from the looks of that traction bar looking thing that maybe you hit something a little hard under there and the transfer of force from that may have caused your damaged spring.

68sting

Thats an intersting thought. I wonder if a bottom out might cause that. I'll have to talk with vbp to see if that could do this. On another note do these traction bars help? I still have wheel hop.

LIQUIDDRAGON

I would do away with the traction bar and try a different set of shocks. a good set of shocks that is matched to the spring should help eliminate wheel hop. im just a little lost as to what the traction bar is doing for the rear diff since it is bolted to the frame and doesnt really twist.

68sting

I would agree with your assessment. I got a number of parts from a gentleman and this was one of them. My only thought is the cross member bushings could give a little. This would be another point securing the differential and limiting cross members possible movement. I also like the fact it would protect my exhaust in bottom out situations. I realize now it might be breaking my leaf springs though. VBP sell a similar unit. I will ask them if they're selling snake oil or a legit add on.

86atc250r

Is wheel hop a common problem on these cars?

In 20 years I've never had an issue with mine & I've given it plenty of opportunity

LIQUIDDRAGON

I am not sure what shocks you are running but I have heard that the bilstein shocks are the best for the composite springs. The bilstein shocks came with my kit from VB&P BUT since I haven’t driven my car yet I can’t comment on how they perform and can only tell you what I have heard from others.

http://www.vbandp.com/detail.aspx?ID=920

WESCH

Hi

The traction bar can not have any negative effect to the ride nor to the spring.
All it does is holding the differential in position.

The differential is held from rotating around by the rubber grommet to the crossmember in front of it. During hard acceleration , the differential is twisting . The traction bar is holding it tight.

I would ask VB&P to replace this plastic spring on warranty .

And if not, replace it by a different make spring , like TRW .

Rgds. Günther

MN80Vette

Everything between the rear wheels of my '80 has been rebuilt or replaced except the diff internals - trailing arms, bushings, shafts, bearings, spring, gas shocks, etc. After all that, wheel hop was still a big problem. A good set of shocks matched to the spring did NOT eliminate wheel hop. (BTW, I have a GM 350/330 HO crate, a street&strip clutch, and the stock-rebuilt BW Super T-10 4-speed.)

I made my own traction bar out of a solid motor mount in front, a mounting bracket I fab'ed in the back, and a double-Heim bar in between. Nothing else was changed. Now I have absolutely NO wheel hop. The twisting force on the diff is transferred directly to the cross member by the traction bar to the solid motor mount on the cross member. The adjustable length bar allowed me to preloaded the traction bar.

I'm sold on traction bars for years with rubber or poly batwing mounts instead the solid disk on previous years. I just would not buy the monster bar sold by VBP and others. Besides, they didn't make it for the spring mounts with 3 bolts instead of the earlier 4 bolts. You can make your own for less $$ and with more clearance.

BTAL

Exactly what shocks are on the car? How old are they? Standard and/or worn out shocks will be too hard on a composite spring.

Vesa

Hi
What is the function of that bar??? I´m slow to understand...I know...
Anyhow if the bar is front and rear mounted like in your picture into the rear end housing, nothing is ever even trying to move since the rear end housing is "one peace" - or what movement is the bar reducing???
If the front of the bar would be mounted or welded a bit more ahead to the car frame then it would prevent rear end flexing due to the non solid mounting bushings in front of the rear end...

theandies

Thats what I did on mine.

My first spring started coming apart slightly but not any where as bad as 68stings. I bought my VBP spring from Van Steel and they were great about replacing it no questions asked only if I used VBP installation instructions which I did. I've had the replacement spring on for about 2 years without any problems.
Here is what happened to mine:


I don't have a metal heat shields but the header wrap is a least 6 inches on either side of where the pipes go below the spring area. It's hard to tell in the picture. I also took a contact temp probe to the pipes and the spring when I first installed it and the spring surface temp never exceeded OAT. The pipes right before and after the header wrap was around 300 degrees F but the header wrap was just at 100 degrees F. The pipes are about 5 to 6 inches from the spring too.