stock axle strength and brake upgrade questions

[79malibu]

hi guys,

my first question is what seems to be the invisible line for power wise on longevity on the stock 7.5 axles? just wondering what the most power someone had on stock axles before they gave in. i have a 355 pushing under 400hp with a mildly built 700r4 with a 2k stall going into a new 3'' D shaft and freshened 7.5 10 bolt with 3.42 gears and a detroit true trac locker caped by a girdle. rear tires are 275/60/15r streets and i can spin them on the street when shifting into 2 + 3 gears. now i don't drive like and *ss and usually just cruise but get on it here and there. i can feel the car is loaded with TQ but i'm starting to worry about sh*t i haven't addressed yet breaking.

secondly. with that locker in the rear it hard to do a standing burnout. i mean the car just pushes. my front brakes can't hold her even if i am leaning back trying to break the seat and force the pedal through the floor! now my brakes are all stock and in new condition so i was thinking about brake upgrades for the front while retaining the stock height spindles. for example, i was thinking of a new b body caprice master cylinder and switching to stainless brake hoses but i don't know of anything yet to get bigger brakes that can just drop in basically. on the rears, iirc on a past topic here a guy can swap the rear brakes from a b body to the g body. just need to reuse the backing plate and all hardware etc. and then you have the b body 11'' drums instead on the g body 9 or 10'' drums? let me know what you think

 

[G_Body_Enthusiast]

you have many brake options and many of them have bolt in kits.

www.flynbye.com is a site to check out. plenty of bolt in kits for front and a couple for rear. and who wouldnt want corvette brakes on their car? 12 13 and 14" options. leaps and bounds better than the first upgrades thought of for these cars, like the rear drum swap from a b-body. and the prices are pretty reasonable.

 

[Blake442]

secondly. with that locker in the rear it hard to do a standing burnout.

More motor!!

I've heard mixed reviews on how long the 7.5 will last.

Some people run more power than you and have been fine.
Others seem to be able to blow them up with stock 305's.
I've never had a problem with any of the 9 cars I've had with 7.5's, but then again they were all stockers and the only one that makes good power has an 8.5 under it.

I guess roll the dice and see what happens...

 

[axisg]

If you have trouble now spinning the rear wheels under load then bigger drum brakes will make it worse. Isn't the B-body a diff bolt pattern as well ??

What I did for brakes were both driveway mods and still allows me to use my stock 15" wheels.

98-03 - S10/Blazer front spindles with dual piston calipers which were dead simple and done in under an hour each side with no alignment afterwards ( cost appx $1k with new bearings, rotors & pads in addition to used spindles ,calipers, and flex lines ).

In the rear I used LS1 Rear brakes from a 98-03 Fbody. They took a little longer as you have to pull the axles out of the tubes to change the backing plates but that was done in about 2 hours. ( cost appx $ 300.00, brake assembly bought used on fleabay + new flex line, axle seals, and I replaced the hard lines on the axle tube for good measure )

As far as burnouts the theory is that the rear disk brakes don't have the clamping power of a drum brake at a dead stop so rear disks are actually easier to spin under power. Drum brakes have a much larger surface contact area but they also overheat quickly and no good way to dissapate the heat which results in brake fade.


Everything I read on the 7.5 states that they break up under shock load. So no slicks, and no spinning wheels from wet onto dry roads and avoid wheel hop.

 

[MD13ailey]

I'm running about 375hp on a 255 60 15 on my car with a spool and i race it on street tires and run around on the street and i havent broke my 7.5 yet....

 

[84GP455]

I have a Pontiac 455 crate motor with about 400hp and i am currently on my 3rd 7.5 rear end. The spider gears broke on both of them while getting on it around a corner. The first sign was they went from posi burnouts to single trac burnouts, in other words the posi unit seemed to weaken or the clutches wore and it was mostly single traction then they broke. So maybe i should have changed the fluid and put the additive in them and they might have lasted longer, granted they both were used units from the junkyard. This 7.5 i have in there now is from a 85 cutlass posi unit with 2.41 from the junkyard. I currently have a 8.5 Grand National rear with 3.41's and rear disc setup which i will be installing very soon.

 

[79malibu]

yea i think the caprice bolt pattern is different now. anyone try using the b body master cylinder or use the oversized gm metric calipers that are a 2.75 bore vs stock 2.5'' by us brake i seen in jegs and summit websites?

 

[79malibu]

http://www.summitracing.com/parts/SSB-A181/
would this be worth the money? instead of a 2.75'' bore caliper get a twin piston caliper of 1.49'' bore? or would i be better off getting the stock type overbored as below.

http://www.summitracing.com/search/Year ... Rank%7cAsc

what also is the best rotors and pads out there? or just best bang for the buck anyhow since i'm not road rally driving. iirc i read someones' post that ceramic pads don't leave dust on the wheels? are they also quiet? these cheap house brand(jegs/summit) drilled and slotted rotors any better than a standard oem rotor?

 

[79malibu]

Re: stock axle strength

anyone ever twist off or broke the axles splines or nub for the C clip retainer on a 7.5/7.6 rear with 26/28 spline axles? except for the splines the actuall shaft is still the same thickness isn't it? between the 26/28?