Author Topic: 66 non power brake diagnosis (Read 12951 times)

anychevy · « **on:** March 21, 2012, 04:49:31 PM »

Before I start pulling things apart and ordering parts, I though I should get some advice first.
#1 Get in the car and the brake pedal goes straight to the floor, but will pump up and hold, but sometimes slowly drops to the floor again.
Inspected all brake lines, hoses and calipers for obvious leaks, but all dry.
Haven't noticed any loss of fluid in the resevior, but it's only been a day.
#2 Brakes pull hard to the right and again, nothing jumps out as obvious, calipers look o.k. no leaks and the hoses look good on the outside.
It feels like the right caliper grabs the rotor and a split second later the left grabs. Very scary !
I think there's air in the system and the piston cups in the MC are probably gone, but it's the pulling to the right that has me baffled.
The previous owner said "it's always been like that"
Any ideas if (like I suspect) bleeding does nothing ?

sirfixalot · « **Reply #1 on:** March 22, 2012, 08:15:19 AM »

Probably the flexible hose on L/hand side is collapsed/blocked inside. Replace all four if one has gone. Use a bottle of fluid on front & another for rear to flush out all old fluid.
Maybee a siezed piston in l/hand caliper? Mixed set of disc pads, different composition.
A new master cylinder is only about $150 probably the old one has rust in the bore down past where it would normally operate when pedal goes to floor causes small scores in seals which allows fluid past seal

77CVT · « **Reply #2 on:** March 22, 2012, 09:44:55 AM »

Grab a mate, clamp all 4 lines and press on the pedal while your mate releases one corner at a time. You should feel the pedal move slightly when the clamp is released (normal) and when you get to the dodgy corner the pedal will move a lot.

If the pedal moves a lot when all of them are clamped, it is the master cylinder.

If you have a dodgy caliper, get online and buy some new ones! I've never had any real success reconditioning old calipers. I had a similar problem with my 71 and bought new ones - no problem since! (and it cost less than getting them reco'd)

May as well get new rubber lines while you are at it. For $100 for 4 it sure beats $40 each to get made up here in Aus.

anychevy · « **Reply #3 on:** March 22, 2012, 12:07:52 PM »

Quote from: 77CVT link=topic=9105.msg1045942293#msg1045942293

If you have a dodgy caliper, get online and buy some new ones!
May as well get new rubber lines while you are at it. For $100 for 4 it sure beats $40 each to get made up here in Aus.

Thanks sirfixalot & 77CVT
Do you guys know a good US source for brake components ?
I'll definately get pads, hoses and maybe front calipers (the back look pretty new)
The MC is just the single outlet type, so I'm guessing that won't be too hard to get fixed locally ?
LHF caliper looks newer than the RHF and the pads are different brands, so it looks like "Bubba" had a go at it.
I'll bleed it first, just in case there's air. Then start start testing things.
Thanks again
Cheers

bfit · « **Reply #4 on:** March 22, 2012, 01:01:25 PM »

Mate can you post of photo of the master cyl.
single out let does not sound rite But I am not up on variations on your model

IN any case a single out let would not supply adequate volume to all four calipers.

Bfit

anychevy · « **Reply #5 on:** March 22, 2012, 03:07:29 PM »

Quote from: Bfit link=topic=9105.msg1045942295#msg1045942295

Mate can you post of photo of the master cyl.

Same as this, single outlet in front.
http://www.cssbinc.com/1965-1966-corvette-master-cylinder-non-power-brakes.aspx
The dual oulet MC was standard with power brakes from 65 and non power brakes from 67

I just had another look over the brakes and the LHF calliper is now leaking from somewhere (it wasn't before I drove it yesterday)
So, I'm now thinking a complete front brake kit is what's I'll need, 2 callipers, 4 hoses, 4 pads and a master cylinder.
The back looks all pretty recent, so I might just get hoses just to be safe.
Where is the place place and which type of calliper ? SS O ring or "LIP" seals ?
Thanks guys.

77CVT · « **Reply #6 on:** March 22, 2012, 04:53:23 PM »

Clamp the LH line and see if you have pedal - if not keep going around until you do. If you don't then start with a new MC.

Any flex in a rubber line will cause a slight pedal drop.

If you can get o ring caliper go for those. I got mine from Ecklers but shop around (freight will be heaps!). Not sure if your club gets a discount.

sirfixalot · « **Reply #7 on:** March 22, 2012, 05:41:39 PM »

Ponti world in wollongong https://pontiworld.com.au/usgmsp/index.php?cPath=239_242&sort=2a&page=2has the calipers recoed no exchange I have a single system master cylinder off a 65 which was working when removed for upgrade to power brake dual system, you could get that one recoed to save time
Ponti world booster & master cylinder $357, Caliper front $237 & includes a set of pads. Hoses for 68-82 $73 for 4 not sure what the difference is for 65.Ecklers lists them for 63-82
You would also need the proportioning valve & a couple of new hard lines

anychevy · « **Reply #8 on:** March 22, 2012, 06:09:55 PM »

Quote from: sirfixalot link=topic=9105.msg1045942298#msg1045942298

I have a single system master cylinder off a 65 which was working when removed for upgrade to power brake dual system, you could get that one recoed to save time

Mate, that would be a huge help. I'll U2U
I don't think I need a proportioning valve, the single system uses a smaller diameter front line from the distribution block (I think)
But I'll check the AIM and hard lines appear all o.k.
Dave has the calipers (with pads) and hoses (same) in stock, so I might get this thing to stop this weekend, with any luck.
And I have to drive through Sutherland to get to Dave :drink:
So please give me a call.
Cheers

Scott · « **Reply #9 on:** March 23, 2012, 09:09:40 AM »

I've bought lots of stuff from VBandP including braided flexi lines and o-ring overhaul kits. They have specials all the time, which helps. Shipping can hurt though.

anychevy · « **Reply #10 on:** March 27, 2012, 09:27:13 PM »

Replaced both front calipers, pads and new flexi hoses all round.
Still got a little air in one rear caliper (inside bleed nipple frozen solid) but it stops straight and I have a hard pedal now.
Looks like the master cylinder is reasonably new and not causing any issues.
But all 4 rear bleed nipples are rounded, so I need to replace them and bleed the back again.
And man, they hold alot of fluid, used 2 litres !
Does anyone know where I can buy bleed nipples here ? (I like saying nipples) :rolleyes:
Cheers

Scott · « **Reply #11 on:** March 28, 2012, 09:14:30 AM »

I'll have to check, but I think I have a set of new stainless ones to suit C3 calipers that are in my left over parts box.

anychevy · « **Reply #12 on:** March 28, 2012, 04:52:45 PM »

Quote from: Scott link=topic=9105.msg1045942334#msg1045942334

I'll have to check, but I think I have a set of new stainless ones to suit C3 calipers that are in my left over parts box.

Thanks Scott
Same caliper from 65-82 (so I'm told) I need the 4 rears, if you have them ?
Would like to get rego next week and take it down to the nationals if possible.
I sent a U2 with my number so we can work something out.
Cheers

Scott · « **Reply #13 on:** March 29, 2012, 08:57:52 AM »

I'll have a look when I get home tonight and get back to you.

anychevy · « **Reply #14 on:** March 29, 2012, 03:52:45 PM »

Quote from: Scott link=topic=9105.msg1045942337#msg1045942337

I'll have a look when I get home tonight and get back to you.

Thanks Scott
VB&P list the same part from 65-82 front & back, so I guess they're all the same ?
http://www.vbandp.com/C2-C3-Corvettes/C2-C3-Brake-Products/C2-C3-Brake-Components/1965-82-6-SS-Bleeder-Screws.html
Cheers

77CVT · « **Reply #15 on:** March 29, 2012, 04:41:32 PM »

Same same.

Scott · « **Reply #16 on:** March 29, 2012, 08:14:09 PM »

I only have 2 nipples.

I also have 2 of the stainless plugs to go in the bottom holes of the caliper. I'm not sure why I only have enough for 1 caliper though. Strange.

You should be able to get them from any decent parts store though, or any brake place. Just take one in if they aren't sure.

anychevy · « **Reply #17 on:** March 29, 2012, 10:07:56 PM »

Quote from: Scott link=topic=9105.msg1045942344#msg1045942344

You should be able to get them from any decent parts store though, or any brake place.

No worries Scott
I'll try the 2 bleeders out of the old front calipers if all else fails
That should work.
Thanks for having a look anyway.
Cheers

77CVT · « **Reply #18 on:** March 30, 2012, 09:37:51 AM »

If you are desperate I have got some from Hopper Stoppers before.

anychevy · « **Reply #19 on:** March 30, 2012, 01:43:48 PM »

Drowned them with WD40 for a couple of days, a big pair of vise grips, a bigger hammer and alot of sweat and foul language.
I swaped the front 2 (which were still good) onto the LHR
I'm sure Bubba had a go at this and just gave up. :shake: Anyway, I'll bleed them later and hopefully that's it !
Thanks all for the advice
Cheers