Brake Pedal Travel Issue

[seabeelt]

Thanks guys , GOOD info

[SouthwestSpider]

Okay - so - I've got the spider up on jacks, rear jacks higher than the front. I'll try bleeding them.
One question - does that acorn nut influence the brake pedal travel? Right now my front brakes are not grabbing tightly. The rear brakes seem okay but my pedal travel is down to the floor and I don't really stop.
I've got to get this bleed issue fixed and get some brakes.

[rodman]

This may help you????

The Power Bleeder lets you experience the ease of single-handed brake bleeding. Patterned after the tool used by professionals, the Power Bleeder attaches to the fluid reservoir of your clutch or brake cylinder and pushes fluid through the system, purging any air present and flushing it completely. Two-qt. container, pump and pressure gauge assure that the job is done right the first time. Instructions included.


http://www.international-auto.com/brake-bleeder.cfm

[burgandy81]

That is a great tool although I am not sure the power bleeder is the right tool for this particular issue.

As described to me, the air is trapped at the end of the MC which is above (elevation when sitting) the inlet and outlet holes of the MC. Forcing fluid through the system will not free these bubbles.

The procedure this application (in my very uneducated opinion) is to tap the MC and try to encourage the air to move UP the soft lines into the reservoir.

Any thoughts from the professionals or those with more experience?

[mgbgtn]

One step no one has mentioned is did you bleed the master before hooking your brake lines back up. If you don't do this first the brakes will not bleed properly.

[SouthwestSpider]

This is a great dialogue! I did do a bench bleed of the m/c before putting it on. I haven't had the chance to get at the bleeding process with the car at an angle. I've got a power bleeder as shown. I have also been given a suggestion that a vacuum pump at the bleed screw is another option.
I will give you an update as soon as I've followed through on the bleeding process.
Thanks to all - keep the good ideas pouring in...

[burgandy81]

I agree, nice to see all these ideas!

One idea that a friend and I have tried is to use a pump style oil can to force brake fluid IN through the bleed screw and try and force the bubbles up.

This seemed to work (fluid went in) but it did not solve my issues.

[Nev]

May I join this club of Spiders with pedal travel?
I had the front of my spider in the air for a few weeks changing all the wishbone bushes and at the same time changed the front disks and brake pads. Once the car was back to the ground I have the same issues as you guys. It seems the air lock in the MC sounds very likely as I hadn't touched the servo or mc other than to take the lid off the reservoir to aid pushing the calipers back in order to fit the new pads. This could have introduced some small air bubbles into the MC. I'll raise the rear of the car on Sunday and see if I can dislodge the bubbles back into the reservoir.
Really good to see others with the same issue before buying a new servo or mc!

[saavejo]

I have the same issue with the low pedal. After rebuilding the front calipers and installing new rubber brake hoses in the frontand bleeding the system I noticed the brake pedal travel is too low. One thing that I was not able to prevent was the lost of brake fluid in the reservoir. The brake fluid reservoir emptied all the way to the bottom as the brake fluid leaked ot of the open brake lines interfacing with the calipers. I also bled the rear brakes by jacking the car one side at a time. Please advise. Thank you!

Jose 1977 Spider

[opus10583]

Hi,

Does anyone have an update of their progress or learnings with this issue?

Thanks,
Mark

[divace73]

I think I have the same issue, do we just have the rear of the car higher and the air will work its way out,
or do we need to pump
or complete re-bleeed?

[burgandy81]

Minor update.

I have had my car lifted at the rear and tapped the MC repeatedly, left the car elevated for several hours with no effect.


Research continues and my next effort will be to bench bleed the MC with modified brake lines feeding back into the reservoir. This makes sense to me for modern MC that have convoluted fluid chambers for ABS but it is hard to see the need in a traditional MC such as the spider. Alas, "the internet" says this is very good idea for many situations where a traditional brake bleed does not create the desired pedal feel. Thoughts?


Looking at the hard brake lines I am wondering how one would ever get air out of the large loop that forms the transition from the top of the MC down to the calipers. In my mind the fluid would just force the bubble into either side of the steel tube then the air would "float" back up to the top of the inverted "U" bend. Am I understanding this correctly? If so, what is the best approach to solving this conundrum?

[splitime]

I'll be dealing with a "pedal works on the floor" issue soon.

Anyone have updates? Is this looking like more of a booster/servo issue? (mine does seem to stall at stops when hitting the brake pedal if I remember from the one and only drive I've had in the car so far)

[burgandy81]

Solved!

In my case the booster push-rod was not adjusted correctly! Thus the full pedal travel was only pushing in the master cylinder partially resulting in very little pressure being built up in the braking system.

See excellent description of the proper set up procedure here;

http://www.international-auto.com/fiat- ... lation.cfm

I was able to make this adjustment in the car. I unbolted the MC and reservoir and was able to turn out the acorn nut one turn. I reassembled, drove it, the pedal us up a little higher and the brakes were better! Repeat procedure and now the brakes are much better!

This may also be the case for some other members on this thread as a couple have mentioned replacing either a booster or MC.

Cheers,

Jordan

[Weelan]

Congrats Burgandy! I'll have to check that once the car is back together.