Spongy brakes

oldie · 29th April 2017, 18:22

Just had replacement front discs, pads and pipes about 100 miles ago. Today after driving about 20 miles the brakes felt spongy. Some resistance at the top of the pedal but then it gently travels to the floor under a bit of pressure. When fully depressed the brakes hold the car at rest but I am less than sure they will bring the car to a halt when underway. However I managed to drive the car home with very gentle braking, putting the gear into neutral when nearing a junction and slow driving. I can't see the "Min" mark on the fluid reservoir but the fluid is about halfway down the angled shoulder below the vertical filler tube.

Master cylinder or air lock?

If the former, are they easily obtained?

stevestrat · 29th April 2017, 18:44

The max level is about halfway down the filler neck of the reservoir, not sure about min. Bearing in mind what you've had done I'd suspect an airlock.

If it does turn out to be a problem with the master cylinder, they are shown no longer available from Rimmers, allegedly All Car Parts Fast has them but I'd take that with a pinch of salt, they have been known to show "ghost" parts. The good news is the same master is fitted to all petrol ZTs and ZT-Ts and 2.5L 75 tourers. See here.

3disco · 29th April 2017, 22:37

Possibly needs a bleed with a t4 it was the only way I could get a decent pedal after a pipe replacement!

HarryM1BYT · 30th April 2017, 02:17

It doesn't sound like your problem, but be aware that new pads will feel a bit spongy until they have bedded in properly. The pad faces need to be worn to match the discs, before full braking is restored - until then, they will have some springiness when applied.

dbt01 · 30th April 2017, 07:30

Oldie's description of the symptoms sounds a bit more than that, I think.
A garage pressure-bleed is the first place to start as 3Disco says, before trying to source (and pay out for) a master cylinder which may well not be needed.

David

roverbarmy · 30th April 2017, 08:20

I thought similar after replacing the front pads and discs. I was going to have a bleed etc., the following week but as the pads bedded in the pedal improved so I didn't bother. It is now back to normal but it did worry me for a few days.

As you have replaced the pipes also, I understand that a bleed using the T4 actually works for the abs side to kick in.
Mike

oldie · 30th April 2017, 09:27

A thank-you to the respondents.

Does anyone know where the minimum fluid level should be? I've attached a sample picture from the internet. The fluid level on mine is below the vertical filler pipe, approximately on a level with the top of the writing. This seems a little low to me. If I decide to top-up: a) what fluid is recommended, and, b) is it ok to mix fluids. The brakes were done by a garage familiar with Rover 75s, but lacking a T4. Perhaps I should have found a T4 user to do the work.

spyder · 30th April 2017, 09:46

The level needs to be halfway up the neck. Any dot 4 fluid can be used/mixed. Why was it so low? a T4 will do it quicker and better to a degree, but not a must in my experience .

stevestrat · 30th April 2017, 09:54

After a lot of image hunting on the internet, the minimum level is just above the join between the top and bottom halves. Not the best photo but you can just about make out the min level marker above the join.

dbt01 · 30th April 2017, 10:40

Silly question maybe, but you have checked the all brake callipers/hoses/nipples are dry, not just the ones they replaced, haven't you David?

David

29th April 2017, 18:22	#1
oldie Loves to post Connoisseur SE v8 auto '54 Join Date: Jan 2009 Location: West Sussex Posts: 488 Thanks: 105 Thanked 56 Times in 41 Posts	Spongy brakes Just had replacement front discs, pads and pipes about 100 miles ago. Today after driving about 20 miles the brakes felt spongy. Some resistance at the top of the pedal but then it gently travels to the floor under a bit of pressure. When fully depressed the brakes hold the car at rest but I am less than sure they will bring the car to a halt when underway. However I managed to drive the car home with very gentle braking, putting the gear into neutral when nearing a junction and slow driving. I can't see the "Min" mark on the fluid reservoir but the fluid is about halfway down the angled shoulder below the vertical filler tube. Master cylinder or air lock? If the former, are they easily obtained?

29th April 2017, 18:44	#2
stevestrat This is my second home ZT260 #243 (resting) Join Date: May 2010 Location: Prestonpans Posts: 22,455 Thanks: 650 Thanked 4,624 Times in 3,358 Posts	The max level is about halfway down the filler neck of the reservoir, not sure about min. Bearing in mind what you've had done I'd suspect an airlock. If it does turn out to be a problem with the master cylinder, they are shown no longer available from Rimmers, allegedly All Car Parts Fast has them but I'd take that with a pinch of salt, they have been known to show "ghost" parts. The good news is the same master is fitted to all petrol ZTs and ZT-Ts and 2.5L 75 tourers. See here. __________________ Steve T4 Location Map

30th April 2017, 02:17	#4
HarryM1BYT This is my second home 75 Contemporary SE Mk II 2004 Man. Sal. CDTi 135ps, FBH on red diesel, WinCE6 DD Join Date: May 2010 Location: Leeds Posts: 17,273 Thanks: 2,160 Thanked 2,061 Times in 1,586 Posts	It doesn't sound like your problem, but be aware that new pads will feel a bit spongy until they have bedded in properly. The pad faces need to be worn to match the discs, before full braking is restored - until then, they will have some springiness when applied. __________________ Harry How To's and items I offer for free, or just to cover the cost of my expenses... http://www.the75andztclub.co.uk/foru...40#post1764540 Fix a poor handbrake; DIY ABS diagnostic unit; Loan of the spanner needed to change the CDT belts; free OBD diagnostics +MAF; Correct Bosch MAF cheap; DVB-T install in an ex-hi-line system; DD install with a HK amp; FBH servicing. I've taken a vow of poverty. To annoy me, send money.

30th April 2017, 07:30	#5
dbt01 Retired Join Date: Jan 2009 Posts: 378 Thanks: 15 Thanked 106 Times in 85 Posts	Oldie's description of the symptoms sounds a bit more than that, I think. A garage pressure-bleed is the first place to start as 3Disco says, before trying to source (and pay out for) a master cylinder which may well not be needed. David Last edited by dbt01; 30th April 2017 at 08:14..

30th April 2017, 08:20	#6
roverbarmy This is my second home Roverless + 1.7D Sportage Join Date: Aug 2014 Location: East Norfolk Posts: 7,050 Thanks: 729 Thanked 2,021 Times in 1,449 Posts	I thought similar after replacing the front pads and discs. I was going to have a bleed etc., the following week but as the pads bedded in the pedal improved so I didn't bother. It is now back to normal but it did worry me for a few days. As you have replaced the pipes also, I understand that a bleed using the T4 actually works for the abs side to kick in. Mike __________________ Oil in my veins! Last edited by roverbarmy; 30th April 2017 at 08:23..

29th April 2017, 22:37	#3
3disco 3disco ROVER 75 CONN TOURER CDTI and ZTT V8 SE LPG Join Date: Sep 2008 Location: chardstock.axminster,devon Posts: 1,493 Thanks: 361 Thanked 94 Times in 85 Posts	Possibly needs a bleed with a t4 it was the only way I could get a decent pedal after a pipe replacement!

30th April 2017, 09:46	#8
spyder This is my second home 75 CDT Auto Tourer , Rover 45 , Astra, Zaffira, Chev Captiva Join Date: Mar 2011 Location: Wilts Posts: 3,342 Thanks: 203 Thanked 436 Times in 360 Posts	The level needs to be halfway up the neck. Any dot 4 fluid can be used/mixed. Why was it so low? a T4 will do it quicker and better to a degree, but not a must in my experience . __________________ Chrome skull caps, EGR cleaned (original housing), Mondeo lower mounting, 12V outlets in the armrest and tourer boot, cat fixed, working FBH, Lidl plenum covers, DD with reverse camera.New speakesr/Tweeters with MDF rings. wood dash, Memory leather seats, wooden finished steering and handbrake, Xenon headlights.

30th April 2017, 09:54	#9
stevestrat This is my second home ZT260 #243 (resting) Join Date: May 2010 Location: Prestonpans Posts: 22,455 Thanks: 650 Thanked 4,624 Times in 3,358 Posts	After a lot of image hunting on the internet, the minimum level is just above the join between the top and bottom halves. Not the best photo but you can just about make out the min level marker above the join. __________________ Steve T4 Location Map

30th April 2017, 10:40	#10
dbt01 Retired Join Date: Jan 2009 Posts: 378 Thanks: 15 Thanked 106 Times in 85 Posts	Silly question maybe, but you have checked the all brake callipers/hoses/nipples are dry, not just the ones they replaced, haven't you David? David

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