Red89gt

I had to send my front 2 calipers out for a re-powder coat and was wondering if I need to bleed all 4 corners or will it be okay to just do the fronts?
If okay to just do fronts do I start with the right or left or does it matter?
Car is a 2010 grand sport - thanks.

eboggs_jkvl

Corvette RR, LF, LR, RF Check them all to be totally safe.


Elmer

JCtx

Is that what the service manual says? It's usually from longest to shortest path, with the brake module on the driver's side, it'd be RR, LR, RF and LF. That pattern was ages ago, when the 'X' dual circuit federal requirement was external. But to be quite honest, the order is of little relevance IMO (especially if you're bleeding the system regularly, like you should ).

And yes, if you're going to bleed, bleed the whole system. And do it every 2 years at the most.

Finally, remember the GS has TWO bleeding valves on each caliper. I'd be nice for somebody with a service manual to post the procedure, so you follow it by the book. Good luck.

eboggs_jkvl

Yup, right from the service manual. Weird to us old guys but we're never too old to learn new tricks, right?

Elmer

JCtx

More likely GM never bothered to revise it . But again, it makes little difference (if at all). Hey, what does it say about the 2 valves on each caliper? Which one first? Just curious.

eboggs_jkvl

My Wilwoods have double bleed screws and they say to bleed the outboard first then the inboard screw.

Elmer

BEZ06

Hi Elmer

Well.....there are some owners that are older than me and you!!! They are incapable of accepting new technology and are completely unable to "learn new tricks"!!!

Like you said, the Service Manual procedure is RR-LF, then LR-RF, and that's due to the baffle in the master cylinder that separates the fluid into those two separate circuits. In the event, say, the LR brake hose ruptures, the fluid on one side of the baffle would be depleted and the brakes on the LR and RF corners wouldn't work. However, fluid would remain on the other side of the baffle so the other diagonal circuit brakes would work so you could stop the car.

As far as which bleed valve to bleed first on the fixed calipers of the J56 system on the Z06 and GS, you can see in the Service Manual procedure that it says to do the inner first, then "repeat steps 5-11 for the outboard bleeder valve".

So.....that's what the SM says!!!!

Butt.....does it really matter??? I don't think so, unless maybe youre doing the automated procedure using a Tech 2 to cycle the ABS valves to bleed the ABS circuits.

If you bleed the RR caliper first, the system doesn't know which one you did, and with that baffle in the m/c reservoir the fluid in one side won't affect the fluid in the other side, so if you bleed the LR second I dont think it will affect the overall bleeding of the system at all. Normally the fluid is higher than the baffle and it's just one large reservoir until the level goes down enough to separate the fluid into two separate areas.

Same with the Wilwood or GM procedure for the bleed valves. As mentioned, the old school procedure for bleeding is to do the farthest first then work your way to the closest. Doing the bleed valves that way, it would seem that the Wilwood method of outside first should be the way to go, but for some reason GM has the inside first!!

Probably doesn't matter at all!!

Bob


Here is the bleeding procedure out of the 2010 Service Manual. It has the "manual" method (pushing the brake pedal) first, the the "pressure" method (sounds like using something like a Motive Power Bleeder):










And here's the procedure for bleeding the ABS using a Tech 2 to open/cycle the ABS valves:





That procedure above has 2 more steps on the following page that I didn't copy - but they are:

14 - check fluid level

15 - road test the vehicle

JCtx

I guess that was a cheap shot at me, but what the hell are you talking about? 'New technology'? As I mentioned, the dual brake (diagonal) circuit was mandated by the government since the 70s man. And you can basically bleed the freaking valves any order you want, and it wouldn't really matter (it's just to follow a certain order). And further proof GM hasn't revised its procedure for ages is vacuum is the most widely used method for bleeding (a lot quicker, a one-person job, and no possible damage from pressurizing the reservoir), and it's not even mentioned. If you want new technology, the Corvette is the wrong car for that . But sometimes I prefer to own old reliable technology rather than new unproven one . Ignored.

realcanuk

I just put speedbleeders. For 30 bucks bleeding becomes a simple, neat, one person job.

Red89gt

Well not sure if money well spent but took advice and had a motive brake bleeder from summit delivered today to bleed brakes. My other 3 cars are hondas and i understand motives adapter leaves a lot to be desired so most likely this will be a vette only tool in my garage.

Just need my front calipers now. Tracking says they're going to be here by close business tomorrow. I pray I don't have anymore leak issues and the brakes need zero work until fluid flush in a few years. This caliper coating has been a royal pain in my a$$. Have to get it buttoned up by Friday since I leave the country Saturday and with hip surgery when I get back the vette may not move for quite a few weeks.

macguyver

Good luck and hope it turns out well for you- going to attempt to change out all four of mine one day this year when I get enough courage and info- about half way there as of now

Did get a big tip from a friend out west in L.A though-- he says to only do 1 caliper @ a time-- change one and then bleed it before you go to the next one. He's a pretty sharp cookie so I know he knows what he's talking about

Red89gt

What a nightmare, just got my calipers back this afternoon and figured I would hang them and be done, hour tops.

Grab a torque wrench and tighten the brake line banjo bolt and it strips before torque wrench clicks, got to other side and same thing, bolt was run down by hand all the way prior to putting wrench on it as well and a light snug in the threads just gave it up.

I have two freshly powder coated grand sport calipers sitting on the garage floor right now with stripped brake line banjo holes. Life is not good right now, very depressed and upset. I cannot win, I contemplated just leaving the stock color for quite a while just for this reason, now I wish I never opened this can of worms. I was a mechanic both in the service and civilian before going to college back in the day this is about as easy a mod to do to the car that's out there. I will get two new calipers coated, new banjo bolts, etc and reluctantly I will attempt to get the car done yet again.

BEZ06

Dayum!!! Sorry to hear of your problems!

Did you use the stock hoses? If so, I don't know why you had such a problem.

If you swapped to stainless steel lines, what you experienced is a common problem.

Good luck getting back on the road.

I've got a couple sets of front calipers if you need some more. I've got a pair of red Z06 calipers and a pair of GS calipers (the red are brand new, and the silver ones have just a few miles before they were swapped for something different).

I've also got my old worn out red ones.

I got the new ones to replace my worn out ones, but then saw these silver GS ones and decided to go with silver all around.

Problem was that I couldn't find any silver rears.

So....I just got a full set of the new gray ones with black lettering that are available as an option, and those are going on the car.

The old red ones would be good for powder coating, but they need new seals/gaskets and at least one new piston.

The other red pair is new and the silver pair is like new.

Bob

Red89gt

Bob,

Not sure where the train derailed. I have built cars from the chassis up and not had any weird issues like this.
It was the stock lines. I had the calipers powder coated the first go around and put them on and found a leak on each side of the fronts on the crossover tubes in order to tighten the powder came off. Mike said send them back and he would re-coat no charge, all good. I went to put them on and the threads in the caliper for the banjo bolt just couldn't hold is my only thought.
I ran the the banjo bolt down by hand first as always and used a torque wrench, 30 ft lbs, last time and this time. Has to be the threads were bogus and couldn't take more than 2 R&R's or my torque wrench is fubar just enough to put me in a bad place.

I do know just re coating them from silver to red has become very expensive and the car has been down for weeks. Thank you for the offer on your stock pile of calipers. We worked out something and I will be getting a new set coated this week and sent back hopefully by next weekend so I can put them on when I get home.


I am paranoid to even put a wrench on the banjo bolt on the new ones that will be next.

Red89gt

So frustrated right now, 3 bolts total and a system bleed to do this job, really, why has this been such an az ache?

macguyver

This is what makes the forum great

Red89gt

I built fox body mustangs for 20+ years and kept some of the parts even though I am out of it just to help others out. It is nice when you can help others out and they pay the favors forward. I don't plan on tearing this car down but I would help anyone local if I ever ran across someone needing it as much as I can.

Bob - Any suggestions on that banjo bolt tightening? 30 ft lbs too much? Do you do it by feel or do you throw a wrench on it? I really don't think my wrench is bad as some of the crush washers from this episode barely have a crush ring on them. Kind of think and hope it was the aluminum was just weak and gave it up, expensive for me.

I am seriously puzzled on how a 3 bolt job (2 caliper mount & 1 banjo bolt) could go south so bad costing so much money and time. Dropped about $100 in ups shipping alone going back and fourth with stand up guy that has been coating them. So easy I even did a write up for others to tackle the job if they wanted, grrrrrrrrrrrrrrrrrr.

BEZ06

I use a torque wrench for most things - but stuff like bleed valves I dont bother.

30 ft-lbs is the correct spec for that brake hose fitting, so I don't know why there would be a problem.

Good luck getting everything back together!!

Bob

Red89gt

I don't have a way to check current calibration either other than to see if it overlaps any other torque wrenches I have. If there is an over lap I can tighten a bolt at compare break ways on torque thresholds or clicks maybe.

Other than that I would have to buy another wrench I guess.
Ordered new banjo bolts as well just in case. The current ones not going back in.

Red89gt

Well I had a local scale and calibration shop check my torque wrench.
At 30 ft lbs it was actually at 29 ft lbs. Only thing I can think of is 30 ft lbs is too much for a steel bolt into an aluminum caliper and it stripped the threads????

Not sure what to do?

Anyone?