Hey guys, just firing off a few questions back to back here. When we got the 1971 fiat 124 spider all the brakes except for 1 were broken. I was wondering what brakes yall prefer and if it could be worth it to purchase these "performance brakes" I keep hearing about on youtube. Links are welcome!!!
Technical Brakes
- Thread starter vinjones
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Technical Brakes
Keep stock brakes, but maintain the sliding wedges. Stock brakes in good condition are more than up to the job. You could try softer pads to give more pedal feel and progression EBC Greenstuff etc
Thanks! We just finished putting in new calipers, rotors, brake pads, brake hoses (front, rear, and rear upper), and anti rattling hardware. After all that we bled the brake lines and just when we thought we were done and had tightened down all the bleed screws we noticed a leak underneath. The male end of the rear upper brake hose was leaking when we pushed on the brakes. We didn't notice during the bleeding because the pressure was not building up but rather coming out the bleeder valves. Here is a video of the leak. You can see where the metallic looking drip is formed is the connection between the hose and the line (male hose to female line, the side of the hose closest to the rear):
I tightened the hose pretty hard down on with a 15mm line wrench, but didn't notice any other nuts to hold or tighten to secure this side of the hose. Any ideas on a potential fix?
We were rather suspicious that there might have been a leak somewhere when we were bleeding the lines because they would push out fluid when we stepped on the brakes, but then after a few seconds of not pushing on anything a lot of bubbles would flow out of the lines. We just carried on because we assumed that the bleeding hose wasn't airtight. This also adds complexity to the situation because the air bubbles flowed out of the front lines as well as the back on the same delay and the rear upper hose is only connected to the back. What could be the cause?
A couple things about our spider that we don't know are standard are that there are 2 brake fluid reservoirs right next to each other, one only goes to the front lines and the other only goes to the back lines. The second is that when we were pushing on the brakes to bleed them we could hear almost a breathing noise coming from the engine bay. When you pushed the pedal down it sounded like it sucked air in and when you let your foot off the pedal it sounded like it pushed air out. Is this another leak or just the brake pedal hardware doing its job?
I tightened the hose pretty hard down on with a 15mm line wrench, but didn't notice any other nuts to hold or tighten to secure this side of the hose. Any ideas on a potential fix?
We were rather suspicious that there might have been a leak somewhere when we were bleeding the lines because they would push out fluid when we stepped on the brakes, but then after a few seconds of not pushing on anything a lot of bubbles would flow out of the lines. We just carried on because we assumed that the bleeding hose wasn't airtight. This also adds complexity to the situation because the air bubbles flowed out of the front lines as well as the back on the same delay and the rear upper hose is only connected to the back. What could be the cause?
A couple things about our spider that we don't know are standard are that there are 2 brake fluid reservoirs right next to each other, one only goes to the front lines and the other only goes to the back lines. The second is that when we were pushing on the brakes to bleed them we could hear almost a breathing noise coming from the engine bay. When you pushed the pedal down it sounded like it sucked air in and when you let your foot off the pedal it sounded like it pushed air out. Is this another leak or just the brake pedal hardware doing its job?
The Spider has a split circuit brake system to provide some safety inthe event of failure. You need to keep the reservoir completely topped up or you will have to rebleed both circuits
When bleeding the rear be aware the rear axle has a brake proprtioning valve. This shuts off supply to the rear axle under heavy dive to prevent the rear wheels locking. The rear axle needs to be in a specific position details are in a good workshop manual. Also check the valve is not siezed up (quite likely unless well maintained), they are not expensive to replace but need to be set correctly
Its mounted on the RHS just inside the wheelarch, directly above the axle. You will need a workshop manual for guidance on set up.
If the valve is set incorrectly it will affect rear brake performance
@vinjones
The 'breathing noise' coming from the engine bay is from the Brake Booster unit (fitted between the engine firewall and the brake master cylinder) - there is a piston and diaphragm inside that moves when you press the brake pedal causing the sound you're hearing -it's normal, you don't usually notice it when driving. Operating the brake master cylinder (by pressing the brake pedal) can make a slight noise also - this is normal.
Re: problems bleeding the brakes?
When you fitted the rear brake pads and wound back in the caliper pistons, did you ensure that the pistons were correctly aligned in the calipers - obviously there is a wide groove that fits over a 'spud' on the rear of the inner brake pad - but there is also an alignment mark , it's like a deep scratch just above the deep groove, the piston needs to be turned so that this line needs is above the deep groove on the piston - failure to do so will prevent proper bleeding out of all the air inside the caliper body.
Manual bleeding i.e. pressing the brake pedal instead of using pressure or vacuum bleeding equipment, should be carried out slowly, the bleed screw should be lightly closed at the end of the pedal stroke (to prevent air from being drawn back in) before gently releasing the brake pedal, then wait 2-3 seconds before pressing the brake pedal and opening the bleed screw, lightly closing the bleed screw at the end of the pedal stroke and repeat until no air is seen exiting the bleed screw (I'm assuming you're using a clear bleeding tube? so that you can see any bubbles). The brakes should be bled, one brake at a time, starting at the brake furthest from the master cylinder (probably Left rear) and working back towards the master cylinder (on U.S. cars, probably the left front), so LR, RR, RF, LF. Bleed the rear brakes with the parking brake off and don't run the engine when bleeding the brakes. Remember to keep checking and topping up the brake fluid reservoirs as needed. Do not re-use any of the brake fluid that was bled from the system, even the new fluid. When satisfied with the brake bleeding, tighten all the bleed screws to normal tightness - these screws rely on a taper seal so gently tighten only - iirc, the tightening torque figure is maybe only 6? ft.lbs so light finger pressure on a short wrench is sufficient.
Rear Brake Pressure Regulator - referred to in post #4 as a proportioning valve, is operated by the rear axle travel and as advised, it's important that the rear axle is supported on axle stands (jack stands) when bleeding the rear brakes - if the axle is left hanging by supporting the body instead, the brake pressure regulator valve will close, preventing brake fluid flow to the rear brakes ,so you won't be able to bleed them.
I wouldn't be too concerned about this regulator valve at this stage, the existing original adjustment is probably ok and I've never seen one of these valves seize in the closed position - cars left sitting on their wheels for years i.e. with the rear axle loaded will have the regulator valve open, so if it seizes, it'll seize in the open position. As long as you're getting fluid out of the rear brakes when bleeding them, the regulator valve is not seized closed.
Re: Brake fluid leak at rear 3 way union (connector)?
It's always a good idea to clean things down so that you can see things properly. It's especially important to work cleanly on brakes and not allow any dirt, grit or contaminants to enter the hydraulic system.
So, clean down the 3 way union block, check there are no cracks in the block. Over-tightening can crack the al. block. Taper seating type brake fittings don't have to be very tight, it's the meeting of the 2 tapers that does the sealing, not the amount of tightening force.
Are you running out of threads on the hose fitting - there should be a few thread still showing with the fitting tightened.
Check the flexible brake hose fitting that enters the 3 way union - is it exactly the same as the original hose (assuming you haven't discarded the old hose), it should have a taper end and the thread length should match the original. Here's a few pics, note the taper seating in the 3 way union block, the hose end taper fitting and the amount of threads still showing above the 3 way union block with the brake hose installed and tightened :-
If after fixing any leaks and bleeding the brakes as I've suggested, you are still having problems with bleeding the air out of the system, it's possible that the master cylinder has failed usually due to it's rubber seals having worn out or become damaged.
When bleeding the brakes manually, the brake pedal travels down to the floor, i.e. further than it's normal amount of travel. With age, the internal bore of the master cylinder can suffer from corrosion (rust) or a build up of scale in the section of the bore that the seals don't traverse in normal operation of the brakes. However, when you manually bleed the brakes, the pedal now travels all the way to the floor, the cyl. seals run over the damaged cyl. bore and are themselves damaged - it doesn't take much wear or damage to a seal lip/surface to cause a problem. To avoid the risk of possible cyl. seal damage, many recommend to either pressure or vacuum bleed brakes especially on older cars whose master cylinder may have some bore corrosion.
When you get the bleeding of air completed, it's time to adjust the rear brake pads and the parking brake, here's how I do it:-
Ensure that the parking brake is fully released, check that the p/brake operating lever on each rear brake caliper are fully off (against their stops), if necessary, slacken the p/brake cable to achieve this.
Repeatedly press the brake pedal to adjust up the rear brake pads to the rotors.
When satisfied that the pads are adjusted correctly (i.e. normal brake pedal travel only), adjust the parking brake cable to where 5-7 clicks on the p/brake lever ratchet applies the p/brake fully. Check that neither rear brake is dragging/binding, if so, back off the p/brake cable adjuster.
Finally, re-check the brake fluid reservoir levels, adjusting up the rear brake pads may cause the fluid level to drop in the rear brake fluid reservoir.
Before taking the car for a test-drive, apply and hold the brakes on hard, the pedal should stay firm and not sink.
To do a quick check on the operation of the brake booster? Press brake pedal a few times and while holding it down, start engine - the pedal should sink slightly, indicating that the brake booster is working normally.
Re: Rear brake adjustment
I forgot to mention - after pumping the brake pedal to adjust out the rear brake pistons, you'll need to operate the parking brake lever several times to cause the automatic adjusters inside the rear brake caliper pistons to adjust up. But, as I've already mentioned, in order for these automatic adjusters to work correctly, the parking brake operating levers on each rear brake caliper need to be able to return to the fully off position with the parking brake released. Do not adjust the parking brake cable to adjust the parking brake lever travel, doing this may prevent the automatic adjusters from working, in other words, allow the auto adjusters to do their work first and then adjust the cable to finally set the p/brake free travel.
Some people find that pressing the brake pedal and pulling the parking brake lever at the same time works better in getting the rear brakes to adjust up.
I forgot to mention - after pumping the brake pedal to adjust out the rear brake pistons, you'll need to operate the parking brake lever several times to cause the automatic adjusters inside the rear brake caliper pistons to adjust up. But, as I've already mentioned, in order for these automatic adjusters to work correctly, the parking brake operating levers on each rear brake caliper need to be able to return to the fully off position with the parking brake released. Do not adjust the parking brake cable to adjust the parking brake lever travel, doing this may prevent the automatic adjusters from working, in other words, allow the auto adjusters to do their work first and then adjust the cable to finally set the p/brake free travel.
Some people find that pressing the brake pedal and pulling the parking brake lever at the same time works better in getting the rear brakes to adjust up.
@124BC1 Thank you so much for your awesome reply. That answered all the questions I had and ones I didn't even think of yet, super helpful!
When you mentioned that overtightening the 3 way union block could cause a crack I suspected that that might be our issue. I had cranked down pretty hard on the hose and the joint was still pouring out liquid. I went on Vick Autosports to find a new union block, and then thought I might as well get another upper hose just in case the first one was faulty. However, at the bottom of the page it suggested that we might want to purchase new crush washers. This seemed peculiar because I didn't notice any when I took off the original hose and definitely didn't put new ones on. Furthermore I don't understand how they would crush if we were to leave a few threads showing on the connection between the hose and the block like you mentioned and I noticed when installing. We did use crush washers for the banjo bolts on the front calipers, so it might seem plausible that we needed some elsewhere?
So my questions are: Are crush washers involved anywhere besides the banjo bolts? and is replacing the union block a good guess?
When you mentioned that overtightening the 3 way union block could cause a crack I suspected that that might be our issue. I had cranked down pretty hard on the hose and the joint was still pouring out liquid. I went on Vick Autosports to find a new union block, and then thought I might as well get another upper hose just in case the first one was faulty. However, at the bottom of the page it suggested that we might want to purchase new crush washers. This seemed peculiar because I didn't notice any when I took off the original hose and definitely didn't put new ones on. Furthermore I don't understand how they would crush if we were to leave a few threads showing on the connection between the hose and the block like you mentioned and I noticed when installing. We did use crush washers for the banjo bolts on the front calipers, so it might seem plausible that we needed some elsewhere?
So my questions are: Are crush washers involved anywhere besides the banjo bolts? and is replacing the union block a good guess?
