IS IT TRUE THAT?...

Front axle, springs, shock absorbers, wheels, bearings, calipers, drums...
Tuning: suspension, discs, alloys upgrade...
NO parts requests here, please use our V3M BUY & SELL corner
Post Reply
Justin
Posts: 366
Joined: 31 Jul 2008 12:18 pm
Location: Plymouth

IS IT TRUE THAT?...

Post by Justin » 20 Feb 2012 11:36 am

...Before removing a front brake caliper you "MUST" remove the filler cap on the brake fluid reservoir or else the following will happen: The piston will be pulled back in order to remove the front brake caliper causing the brake fluid in the reservoir to rise, which in turn will blow the seals inside the master cylinder!
1988 340 1.4 DL

(I suffer with O.C.D. which makes me obsessed with fine detail)

(Diagrams or photos are far more helpful to me when it comes to cars)

User avatar
Speedy88
Posts: 4057
Joined: 04 May 2009 11:52 pm
Location: Bristol

Re: IS IT TRUE THAT?...

Post by Speedy88 » 20 Feb 2012 03:24 pm

No.
'88 340 Williams (Sold)
'85 360 GLS - Drift project (Sold)
'77 Colt Sigma
'96 940 Drift project

macplaxton
Posts: 3283
Joined: 09 Feb 2008 02:29 am

Re: Is it true that?...

Post by macplaxton » 20 Feb 2012 03:41 pm

Been on the Haynes again? sm4
72 DAF 44 Estate 78 Volvo 343DL Black BeautyImageImage
82 Volvo 343DL CVTImageImage 88 Volvo 340DL Diesel

Ride_on
Posts: 2262
Joined: 26 May 2009 05:34 pm
Location: Belfast, N. Ireland

Re: IS IT TRUE THAT?...

Post by Ride_on » 20 Feb 2012 08:51 pm

Definitely not necessary for removing callipers, they just slide off the pads.

Not sure what would happen if the filler cap was not removed and it filled up when you where compressing the pistons for new pads, there is a vent hole so presumably the fluid would just spurt out. Normally the braking system should remain sealed from each fluid and pad replacement so it should not need extra fluid hence have the space for fluid to go back in, but if you are a habitual topper upper then maybe wise to remove some. If will go on fire if it hits a hot exhaust.
1980 345 DL_______1987 360 GLE (project car restored to GLT spec and B230FT'd)
1984 360 GLT______1987 360 GLT
1983 360 GLS______1989 360 GLE
1985 340 GL_______1986 340 1.4
1985 360 GLS______1995 940 SE 2.3 Turbo Estate (daily)
1987 340 GL 1.7

Justin
Posts: 366
Joined: 31 Jul 2008 12:18 pm
Location: Plymouth

Re: IS IT TRUE THAT?...

Post by Justin » 21 Feb 2012 05:04 pm

The reason I asked is because I had my front offside wheel bearing replaced on thursday last week by a cheap local mechanic and my brakes have been "REALLY" spongy ever since. When I checked my oil and water the day after he'd done the work I noticed that the area on and around my brake fluid reservoir was soaking wet with brake fluid! I took the car back to him that day and he said it couldnt have been caused by the work he'd done as he hadnt detached the brake hose. He also said the wetness around my brake filler reservoir would have been caused by the pistons re-adjusting after he'd put the caliper etc back on.

A friend of mine who's good with cars but very busy made time to help me bleed my brakes on sunday. Apparently he had a problem getting any brake fluid to come out of the nipple where the o/s wheel bearing had been replaced and also at the n/s nipple. He didnt try bleeding the rear nipple as he was convinced my master cylinder was knackered due to the work the cheap mechanic had done by NOT REMOVING the brake fluid filler cap. I know for a fact the mechanic didnt do this as I watching him the whole time.

Im gonna try and bleed the entire system starting at the back like my haynes manual says moving to the front left nipple finishing on the one nearest my master cylinder. If my brakes are still spongy after that then I'll replace the master cylinder.

I rang the mechanic I'd used this morning about whether he'd bleed my brakes seeing as they were fine before he'd done the work and he told me to F*** Off and stop bothering him!! As you can guess I wont be using him again...
1988 340 1.4 DL

(I suffer with O.C.D. which makes me obsessed with fine detail)

(Diagrams or photos are far more helpful to me when it comes to cars)

Ride_on
Posts: 2262
Joined: 26 May 2009 05:34 pm
Location: Belfast, N. Ireland

Re: IS IT TRUE THAT?...

Post by Ride_on » 21 Feb 2012 10:14 pm

Thats normally the reaction of bodgers, likely something has gone wrong. The pistons do not 'readjust' by any significant amount, seems he has pushed them back in alot and not checked the fluid level, which he should have done as it can cause a fire. I can't say its caused the problem, but anything is possible.

If the brakes are working atall, then you should be able to bleed them. Fluid should come out of the bleed nipple under gravity alone, possibly a blockage somewhere. Maybe a piece of rubber came of inside, dirt or he has damaged the flexihose.

Another possibility is damage to the master cyl seals. If you push the pistons back in to make reassembly easy, and then push the pedal all the way down to get them back into position it can move onto an unworn part of the master piston and damage the seals. Just read about this recently, I normally don't worry about it and have never had a problem, even in 200K+ cars.
1980 345 DL_______1987 360 GLE (project car restored to GLT spec and B230FT'd)
1984 360 GLT______1987 360 GLT
1983 360 GLS______1989 360 GLE
1985 340 GL_______1986 340 1.4
1985 360 GLS______1995 940 SE 2.3 Turbo Estate (daily)
1987 340 GL 1.7

macplaxton
Posts: 3283
Joined: 09 Feb 2008 02:29 am

Re: Is it true that?

Post by macplaxton » 21 Feb 2012 10:21 pm

Ride_on wrote: which he should have done as it can cause a fire.
Never mind fire, it's bloody like paint stripper. sm2
72 DAF 44 Estate 78 Volvo 343DL Black BeautyImageImage
82 Volvo 343DL CVTImageImage 88 Volvo 340DL Diesel

User avatar
Chris_C
*** V3M DONOR ***
Posts: 9600
Joined: 18 Jun 2004 11:53 pm
Location: South Coast, UK

Re: IS IT TRUE THAT?...

Post by Chris_C » 21 Feb 2012 11:43 pm

Ride_on wrote:Another possibility is damage to the master cyl seals. If you push the pistons back in to make reassembly easy, and then push the pedal all the way down to get them back into position it can move onto an unworn part of the master piston and damage the seals. Just read about this recently, I normally don't worry about it and have never had a problem, even in 200K+ cars.
I've lost a master cyl to this before :(
'89(G) 340 GLE B172k
'03 S60 D5 SE, '91 (J) MX5, 1954 Cyclemaster
Ex:
'89(F) 340 GL F7R (ex B172k) - Fake -> SBKV 300 Runner Up 08, 12; '91(H) 340 GL B14.4E - Kar; '88(F) 360 GLT B200E - Jet -> BKV 300 Runner Up 09; '89(G) 360 GLT B200E - Beast

Justin
Posts: 366
Joined: 31 Jul 2008 12:18 pm
Location: Plymouth

Re: IS IT TRUE THAT?...

Post by Justin » 22 Feb 2012 05:08 pm

Ride_on wrote: If the brakes are working atall, then you should be able to bleed them. Fluid should come out of the bleed nipple under gravity alone, possibly a blockage somewhere. Maybe a piece of rubber came of inside, dirt or he has damaged the flexihose.

Another possibility is damage to the master cyl seals. If you push the pistons back in to make reassembly easy, and then push the pedal all the way down to get them back into position it can move onto an unworn part of the master piston and damage the seals. Just read about this recently, I normally don't worry about it and have never had a problem, even in 200K+ cars.
My brake pedal travels very loosely to the floor on first starting the car which I've never experienced before then the brakes gradually tighten but the pedals still spongey. The brakes work and I could do an emergency stop if I had to, its just that they feel much spongier than before my wheel bearing was replaced.

Im not too good at working on cars but have bought a Gunson Eezibleed "one-man brake bleeding kit" from Halfords which I'll attempt tomorrow as my friends too busy to help me. If my brakes are still soft afterwards then I'll replace the master cylinder. I was lucky enough to be able to get a secondhand one from a red 3 door 340 with the same E-reg plate as mine which has laid immobile in an old farmers field for probably 14 years! The brake fluid reservoir on it was empty/dry probably caused by me removing the front o/s suspension leg from the same car back at the end of the summer 2011, if memory serves me correct I just cut the brake hose in order to remove the leg!!

Regarding pushing the pistons back in to make reassembly easy, I reckon thats exactly whats happened as after he'd reassembled the caliper etc he asked me to push my brake pedal right to the floor and I clearly remember it being as soft as butter and travelling rapidly to the floor. How are you supposed to reassemble the pistons without this happening?

My friend, who's good with cars, is wrong in thinking that the filler cap "HAS" to be removed before removing the brake caliper then?...
1988 340 1.4 DL

(I suffer with O.C.D. which makes me obsessed with fine detail)

(Diagrams or photos are far more helpful to me when it comes to cars)

User avatar
Chris_C
*** V3M DONOR ***
Posts: 9600
Joined: 18 Jun 2004 11:53 pm
Location: South Coast, UK

Re: IS IT TRUE THAT?...

Post by Chris_C » 22 Feb 2012 06:57 pm

I'd suggest he's pushed the piston all the way back into the caliper so it's easy to slide over the pads. Then, when you got back in the car, you had to push the fluid back into the caliper behind teh piston to get it back into position next to the disc.

If the master cylinder is old, then there will be areas of the inside of the bore that havn't been rubbed by the seals for 20+ years. A small imperfection (be it rust, bit of dirt, whatever) can be enough to score the seal scrapping it. For the same reason, it's possible the "new" MC from the old car will do the same during bleeding, as the inside bore has seen action for the same amount of time. Foggy has recon cylinders if this the case.

I'd certainly try bleeding first however, even if you chance the master cyl flushing the fluid in all the car won't hurt. I always do longest path first, so rears (one bleed nipple for the entire axle), then front passenger, drivers passenger.
'89(G) 340 GLE B172k
'03 S60 D5 SE, '91 (J) MX5, 1954 Cyclemaster
Ex:
'89(F) 340 GL F7R (ex B172k) - Fake -> SBKV 300 Runner Up 08, 12; '91(H) 340 GL B14.4E - Kar; '88(F) 360 GLT B200E - Jet -> BKV 300 Runner Up 09; '89(G) 360 GLT B200E - Beast

Ride_on
Posts: 2262
Joined: 26 May 2009 05:34 pm
Location: Belfast, N. Ireland

Re: IS IT TRUE THAT?...

Post by Ride_on » 22 Feb 2012 10:12 pm

Try testing it without the engine running. The servo changes the feel, and you can run down the vacuum by continual pumping and it will get harder (thats normal).

I have had a master cylinder failure that acted like that, pumping up did work. I think the problem was the rubber inserts for the reservoir to the master cylinder had 'flowed' and blocked the fluid inlet. That might explain the lack of bleeding ability, but I am just guessing.

The pedal should not drop to the floor, you either have air in the system or not enough pressure from the master, or leaking fluid, or a blown flexi. You might be sucking in air somewhere. If you cannot lock the wheels there is something wrong and dangerous. The pedal should be very hard with the engine off (after pumping to remove the vacuum), then drop a bit with the engine on and assistance from the servo.
1980 345 DL_______1987 360 GLE (project car restored to GLT spec and B230FT'd)
1984 360 GLT______1987 360 GLT
1983 360 GLS______1989 360 GLE
1985 340 GL_______1986 340 1.4
1985 360 GLS______1995 940 SE 2.3 Turbo Estate (daily)
1987 340 GL 1.7

Justin
Posts: 366
Joined: 31 Jul 2008 12:18 pm
Location: Plymouth

Re: IS IT TRUE THAT?...

Post by Justin » 23 Feb 2012 02:16 pm

Chris_C wrote:If the master cylinder is old, then there will be areas of the inside of the bore that havn't been rubbed by the seals for 20+ years. A small imperfection (be it rust, bit of dirt, whatever) can be enough to score the seal scrapping it. For the same reason, it's possible the "new" MC from the old car will do the same during bleeding, as the inside bore has seen action for the same amount of time. Foggy has recon cylinders if this the case.
How do I go about getting a recon master cylinder from Foggy if it comes to it? Also is my brake pedal supposed to make a "puffing" sound when I depress it? My brakes feel harder today for some reason but Im gonna still bleed the system tomorrow if the weathers dry...
Last edited by Justin on 23 Feb 2012 07:15 pm, edited 1 time in total.
1988 340 1.4 DL

(I suffer with O.C.D. which makes me obsessed with fine detail)

(Diagrams or photos are far more helpful to me when it comes to cars)

Justin
Posts: 366
Joined: 31 Jul 2008 12:18 pm
Location: Plymouth

Re: IS IT TRUE THAT?...

Post by Justin » 23 Feb 2012 07:14 pm

Ride_on wrote:The pedal should be very hard with the engine off (after pumping to remove the vacuum), then drop a bit with the engine on and assistance from the servo.
Thats exactly what happened when I tried this which is probably a good sign, its just that my brakes seem so much spongier than they were before the wheel bearing was done?
1988 340 1.4 DL

(I suffer with O.C.D. which makes me obsessed with fine detail)

(Diagrams or photos are far more helpful to me when it comes to cars)

morgan105
Posts: 282
Joined: 30 Dec 2004 07:34 pm
Location: Wirral, UK

Re: IS IT TRUE THAT?...

Post by morgan105 » 24 Feb 2012 04:23 pm

It does sound like he's put air in the system. If he's pushed them back without taking the filler cap off and draining some then some of the fluid it will over spill from the bottle. If the lost fluid was not replaced as the pedal was pushed again it may have had too low a level and drawn the air in to the system.
Always best to remove the top and drain some fluid before pushing the pistons back when fitting new pads as removes the risk of over spill. Ride on and Macplaxton are both right in it being a fire risk and acting like a paint stripper.

Bleeding will more then likely sort your problem out but make sure you keep the bottle topped up as you do it otherwise if it gets to low you will drag more air in and you'll have to keep doing it until all air is gone. Don't worry about keeping it really full as you do it cause you can always drain any excess out of the bottle when you are finished.

Justin
Posts: 366
Joined: 31 Jul 2008 12:18 pm
Location: Plymouth

Re: IS IT TRUE THAT?...

Post by Justin » 24 Feb 2012 07:11 pm

morgan105 wrote: Bleeding will more then likely sort your problem out but make sure you keep the bottle topped up as you do it otherwise if it gets to low you will drag more air in and you'll have to keep doing it until all air is gone. Don't worry about keeping it really full as you do it cause you can always drain any excess out of the bottle when you are finished.
Im guessing that the Gunson Eezibleed kit leaves the master cylinder reservoir completely full on completion of the bleeding process meaning the level is over the maximum line? Im guessing you have to drain some out of the reservoir to get it on the maximum line? I suppose a rag would help wick it out to the desired level?
1988 340 1.4 DL

(I suffer with O.C.D. which makes me obsessed with fine detail)

(Diagrams or photos are far more helpful to me when it comes to cars)

Post Reply