Big Mark Posted August 8, 2015 Share Posted August 8, 2015 (edited) Have just replaced my brake fluid with no drama, all air bubbles removed, flushed through 2 litres of new fluid and a nice hard pedal. But, when I turn the engine on I get a soft pedal for the first 2-3 inches of travel and the sound of air escaping as I press the pedal. Video clip link below. https://youtu.be/HEFA_HThLFQ Edited August 8, 2015 by Big Mark (see edit history) Quote Link to comment Share on other sites More sharing options...
Big Mark Posted August 8, 2015 Author Share Posted August 8, 2015 Guessing the servo is faulty and needs fixing/replacing? Quote Link to comment Share on other sites More sharing options...
Benjy Posted August 8, 2015 Share Posted August 8, 2015 If you pump the pedal up so it's hard, keep it held and then start the car, does it sink and the once released, become a normal pedal? Quote Link to comment Share on other sites More sharing options...
Big Mark Posted August 8, 2015 Author Share Posted August 8, 2015 Just tried that. Pump pedal up so it's hard. Started engine and pedel dropped and was exactly like the video clip. Turned engine off and a few pumps and pedal is hard again. Quote Link to comment Share on other sites More sharing options...
MKIV-Supra Posted August 8, 2015 Share Posted August 8, 2015 I Had the same problems some Weeks ago, you can search after it. How Did you changed your fluid? Pumping by foot, vacuum bleeding or with pressure? My Problem was, that my brake cylinder was damaged after i changed the fluid for the first time. Because when you pump it down with your foot, and have nothing under your Pedal, your cylindre works in areas that it never gets there and the Seals getting damaged. I've replaced mine then but has issues with bleeding my brake Pedal. Chris Wilson gave me then a Tipp, to remove my squeal shims because they were Rusty. After that everytging worked fine. But before this i've bleeded my brakes, 3 times by foot, then some times by vacuum and then with pressure set at 0.7bar. If you can borough you an pressure bleeder then try it first with it. I hope your brake cylindre isn't damaged already. But another questition, do you have an J-Spec or an UK-Spec? Quote Link to comment Share on other sites More sharing options...
Benjy Posted August 8, 2015 Share Posted August 8, 2015 Well, pumping it up and the pedal sinking with the engine switched on is normal. Actually part of the MOT test. Does the car stop normally? Quote Link to comment Share on other sites More sharing options...
MKIV-Supra Posted August 8, 2015 Share Posted August 8, 2015 Yeah this is normal. Toyota it selfs, gives you a distance it should have. This is the point, i have to accept with the supra, because i had another brake Pedal feeling in my e91 with steelbraided lines. I dont remember right, but i think 7-8cm from the ground, says Toyota is okay. Quote Link to comment Share on other sites More sharing options...
Big Mark Posted August 8, 2015 Author Share Posted August 8, 2015 (edited) I Had the same problems some Weeks ago, you can search after it. How Did you changed your fluid? Pumping by foot, vacuum bleeding or with pressure? My Problem was, that my brake cylinder was damaged after i changed the fluid for the first time. Because when you pump it down with your foot, and have nothing under your Pedal, your cylindre works in areas that it never gets there and the Seals getting damaged. I've replaced mine then but has issues with bleeding my brake Pedal. Chris Wilson gave me then a Tipp, to remove my squeal shims because they were Rusty. After that everytging worked fine. But before this i've bleeded my brakes, 3 times by foot, then some times by vacuum and then with pressure set at 0.7bar. If you can borough you an pressure bleeder then try it first with it. I hope your brake cylindre isn't damaged already. But another questition, do you have an J-Spec or an UK-Spec? I tried to use a vacuum bleeder to change the fluid 2 weeks ago but it was faulty and I ended up with loads of air in the system so bad that the pedal was really soft, so got one of these and it worked perfectly today. All air out of the system, new fluid flushed through and a nice firm pedal (when the engine is off) Car has UK brakes. Well, pumping it up and the pedal sinking with the engine switched on is normal. Actually part of the MOT test. Does the car stop normally? Car has lacked bite so some time, need to give the brake pedal a hefty prod to get it to stop. Hence why I've changed the fluid and bled the system thoroughly. Edited August 8, 2015 by Big Mark (see edit history) Quote Link to comment Share on other sites More sharing options...
MKIV-Supra Posted August 8, 2015 Share Posted August 8, 2015 The UK Spec has also a Tank for the Traction Control u have to bleed too! Quote Link to comment Share on other sites More sharing options...
Big Mark Posted August 8, 2015 Author Share Posted August 8, 2015 The UK Spec has also a Tank for the Traction Control u have to bleed too! My car is j-spec but with UK brakes, so guessing no additional tank? Quote Link to comment Share on other sites More sharing options...
MKIV-Supra Posted August 8, 2015 Share Posted August 8, 2015 (edited) Then it doesnt have the addional Tank so you're right. Edited August 8, 2015 by MKIV-Supra (see edit history) Quote Link to comment Share on other sites More sharing options...
Big Mark Posted August 8, 2015 Author Share Posted August 8, 2015 So what is that "air" sound that I can hear coming from the pedal when the engine is on? Is it a knackered servo? Quote Link to comment Share on other sites More sharing options...
MKIV-Supra Posted August 8, 2015 Share Posted August 8, 2015 My has the same it's a cracked seal, but this makes only an noise normally. Quote Link to comment Share on other sites More sharing options...
Benjy Posted August 8, 2015 Share Posted August 8, 2015 I'll check mine in the morning but I'm pretty sure by looking at your video mate that it's normal. I was out in my daily earlier and had a listen and that makes the same noise. Quote Link to comment Share on other sites More sharing options...
Benjy Posted August 9, 2015 Share Posted August 9, 2015 Yup - Tis normal mate. Quote Link to comment Share on other sites More sharing options...
Big Mark Posted August 9, 2015 Author Share Posted August 9, 2015 (edited) Ok, I'll take it for a drive this morning. I compared it to the girlfriends merc last night and hers doesn't make the noise, pedal is hard and brakes bite from virtually the very top with engine running. My noise and the few inches of easy travel just seems strange. Edited August 9, 2015 by Big Mark (see edit history) Quote Link to comment Share on other sites More sharing options...
Benjy Posted August 9, 2015 Share Posted August 9, 2015 You know the Supra is 20 years old right? Quote Link to comment Share on other sites More sharing options...
Big Mark Posted August 9, 2015 Author Share Posted August 9, 2015 You know the Supra is 20 years old right? Ha ha. Just taken it for a spin and it stops fine. Still need to press pedal further than I'd like and lacks bite but it stops. Read some peoples reviews of their UK brakes saying great pedal feel and bite, hence my concern Quote Link to comment Share on other sites More sharing options...
Benjy Posted August 9, 2015 Share Posted August 9, 2015 Have you got braided lines? Since fitting Goodridges and a brake stopper to mine with UK's, the pedal feels lovely. Quote Link to comment Share on other sites More sharing options...
Big Mark Posted August 9, 2015 Author Share Posted August 9, 2015 I've got braided lines, fresh quality brake fluid, CW pads and a Carbing strut brace with built in brake stopper. Quote Link to comment Share on other sites More sharing options...
Benjy Posted August 9, 2015 Share Posted August 9, 2015 Seems a bit odd bud. Best bet is get it double checked by someone who can actually see the car but I imagine it's pretty normal. Quote Link to comment Share on other sites More sharing options...
SupraP-Z Posted August 11, 2015 Share Posted August 11, 2015 Ive been thinking the exact same thing since i switched over to UK spec brakes last year. I thought the difference would be night and day - its better but the pedal feel isnt great when compared to newer cars especially the likes of merc etc. I cant count how many times ive bled my brakes and it still feels spongy in comparison. Mine makes that same air escaping sound when pushing down on the pedal, and its also firm when the car is off, but when its switched on the brake pedal moves down towards the floor slightly. Benjy is right on this one, ive just learnt to accept that this is the way the car is lol. Either that or ive done something wrong. Only way to find out is to replace every single brake component with brand new and see how it works then. I have stainless steel braided lines, a cusco brake master cylinder stopper (This just feels like you are pressing the pedal into a brick wall...not a natural pedal feel), UK spec calipers, stock pads and discs and a decent brake fluid pushed through, flushed and bled multiple times. When it bites it does work well, but the pedal travel Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted August 11, 2015 Share Posted August 11, 2015 The air sound *IS* air. The servo is vacuum operated, the vacuum created in the inlet of the engine and stored in the servo via a one way valve. When you press the brake pedal the vacuum pulls the internal diaphragm and this in turn aids the push of the pedal push rod. The displacement within the servo on the pedal side of the diaphragm is replaced by air coming *IN* to the servo, via a filter. This is the noise you hear, air entering the servo to fill the increased volume as the diaphragm moves. Strictly speaking the air rushing in is *PUSHING* the diaphragm. I would say you may not have got all the air out of the hydraulic system, but it's perfectly normal, indeed vital, that on depleting the vacuum by pumping the brake pedal with the engine off, that the pedal drops under a steady sustained pressure, when you start the engine and it makes vacuum in the servo. This shows the servo is in fact working. Quote Link to comment Share on other sites More sharing options...
Dnk Posted August 11, 2015 Share Posted August 11, 2015 No issues with my UK brakes, oe pads and discs with braided lines and Motul RBF600 brake fluid. Vacuum bled with a Mityvac, bled the system after fitting new calipers, discs, pads and braided lines all round and had great brakes from the get go, no squishy pedal of lack of bite once the pads bedded in. The most impressive thing the car did was how it stopped Quote Link to comment Share on other sites More sharing options...
SupraP-Z Posted August 12, 2015 Share Posted August 12, 2015 I need to try vacuum bleeding them. They work absolutely fine and stop really well, just lack of pedal feel lol - Brakes are such a PITA when it comes to bleeding! Quote Link to comment Share on other sites More sharing options...
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