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Help!!!!!! SVA Tuesday
coovey - 27/8/05 at 08:29 PM

I have my SVA tuesday on my velocity. I know it's close but i have been un able to set the brake bias up until now due to other issues.

The problem is
A) The rear wheels are stiff to turn by hand when the car is off the ground weather the brake pedal is depressed or not. I.e there seems to be no difference with brakes on or off. If I put the handbrake on they lock up completely.

B) no matter which way i adjust the bias bar the front brakes lock up at the same point on the pedal travel.

Background.
When bleeding the brakes at the front. They move easily when the nipple is open and i get lots of fluid. When bleeding the rears the pedal is still stiff and i don't get anywhere near as much fluid from them.

Question.

Is this normal for the rears not to lock up on the foot pedal?
Which way should i adjust the bias bar i.e. left or right?

Thanks for your time. Phill

jonbeedle - 27/8/05 at 08:44 PM

Sorry I can't help with your problem, but I thought I'd reply because I bought a chassis and a 1300 xflow off you last year. I sold the chassis to a guy in Essex and funnily enough it's on Ebay again at the moment. I wonder if it will ever get built! I found a powder coated chassis in Glasgow!
The engine you sold me runs as sweet as a nut and I'm getting ready for SVA at the moment.
I hope you get your brakes sorted.
Glad to see you've got you're car built, it's looking great.
Are you still restoring the Mini?
Good luck on Tuesday.
All the best.
Cheers
Jon

the_fbi - 27/8/05 at 09:17 PM

quote:
Originally posted by coovey
Background.
When bleeding the brakes at the front. They move easily when the nipple is open and i get lots of fluid. When bleeding the rears the pedal is still stiff and i don't get anywhere near as much fluid from them.


Presume you are running rear discs?

The handbrake shoes could be binding and making the rear wheels stiff to turn, they'll be a self adjuster which you can back off a couple of clicks through an access hole in the rear disc.

Are you running any kind of restrictor for the rear? (Apart from the bias bar)
Are the bleep nipples on the rear calipers at the top of the caliper and are they higher than any other point of the rear pipe setup (are the flexi's routed higher at any point). If so, you'll get air trapped in the high point and never bleed the rear properly. You'll need to remove the caliper (keeping it attached to the pipe) and bleed with it above the highest point of pipe.

If you think the bias bar is stopping you bleeding it properly, just remove the bar and operate the rear master cylinder manually whilst you bleed the rear.

Brakes can be a right pain to get 100%, but its worth it.

coovey - 28/8/05 at 06:51 PM

Right,

spent a whole day on the damn things and have got no where, unless you count the handbrake being worse as progress.

Thanks to everyone who has replied.

Here's my replys to your comments

Binding, I have had the calipers off and made sure there is no paint etc so the pads can move freely.
As said by mookloid I belive the wheels are stiff because of the LSD i have. As the pads are not even touching the disc when the brake pedal is used or even when it is not. I.e. they aren't binding as they aren't even getting there in the first place.
The pads are located correctly, the tag Hellfire spoke about is in the slot.
I have a constant flow of brake fluid. I even took the calipers off and hung them up so they were the highest point so no air could be left in the hoses as the bleed nipples are at the bottom of the caliper when in position.
I took it for a run round the local car park and did 4 miles to try and bed the brakes but the small amount of surface rust that is on the rear discc wasn't even removed. Proving the brakes aren't even touching the disc.

So the only thing i can think of now is adjustment as the piston can be moved in and out.

Therefore has anyone got any idea how they should be adjusted/setup? |I can't find anything in the haynes manual on the adjustment.

Or any more ideas as to why i have no back brakes?

Thanks

the_fbi - 28/8/05 at 07:09 PM

quote:
Originally posted by coovey
I even took the calipers off and hung them up so they were the highest point so no air could be left in the hoses as the bleed nipples are at the bottom of the caliper when in position.

FYI the calipers are on the wrong sides then. Bleed nipples should be at the top.

Not really a problem, except when bleeding.

coovey - 28/8/05 at 08:49 PM

They are as per the manual. it did say the nipple would be at the bottom but that they would give better braking on the front of the disc.

Thanks

mookaloid - 28/8/05 at 10:21 PM

The Indy calipers are mounted with the nipples low too. Simple enough to take off to turn upside down for bleeding.

I assume the caliper mounting sliders are free to move BTW?

Cheers

Mark

coovey - 30/8/05 at 04:41 PM

After 3 days of messing and getting nowhwere the sva came round and the tester found there were no brakes at the rear.

However the guy was very helpful and knowledgeable he gave us a couple of tips and suggestions as to what may be causing the problem. The re test is booked so i will be fixing the brakes (fingers crossed this week) Will let you know what solves the problem.

Thanks guys for all your help

the_fbi - 30/8/05 at 06:27 PM

I'd suggest removing the push rod for the front brakes so that just the rear is getting pressure.

Then remove a caliper from the rear and see if you are actually getting movement on the pistons. Take care to stick something between the pistons so they don't move too far, you just need to prove they are moving somewhat.

Check they slide freely back into the caliper body too (pump grips work well for pushing them back in).

Do this a few times giving them a good 10mm travel each time.

If both sides work fine like that, bleed them whilst you have them off.

Reconnect the front rod and adjust the bias so its rearmost (keep the calipers off).

Then check they still move, you'll have resistance from the front, but hopefully not a lot and you should be able to get good piston movement still.

If not, somethings wrong with the bias setup.

If thats all ok, adjust the bias more towards the front till you feel its OK. A trip to a MOT place with a brake tester can get the bias setup more accurately when you know the rears are actually working.

Let us know what you find.

ta
Chris

coovey - 3/9/05 at 11:20 AM

As suggested by Stuart the tester we mounted the calipers temporarily in exactly the same position they are on the donor (about 45 degrees on the rear edge of the disc with the nipple facing upwards.) Taped the calipers a few times with a hammer then bled them. And boy did we get some air coming out!. They now work fine and we have set up the bias properly (am taking it to a garage to get it checked properly before the retest.)