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Today I started the Head to toe service on my GS450H while SORNed.
First thing I thought was front brakes. The discs did not look bad looking through the wheels, but I removed the front nearside wheel to do a more thorougher inspection. The discs were not scored or pitted, but had a small lip on the outside edge. 
I removed the caliper, and cleaned the lip off with my angle grinder with a flexible grinding disc. Checking the thickness of the disc i found it to be 28.5 mm, and the minimum thickness stamped on the disc is 27mm so all good there. Next I removed the pads from the caliper. The outside pad came out easily, but the inner pad would not move. I also noticed the inner pad was slightly thinner than the outside. After much levering, and tapping the pad came out. Both pads had more than 50% of material left on them so no need to change them. On trying to push the caliper pistons in I noticed the bottom inner piston was seized, and it's rubber boot damaged. Peeling the boot back showed a rusty piston. Strangely the car past it's MOT Less than 100 miles ago and the brake balance was near perfect, and so past the test without problems. 
Ordered 2 caliper repair kits with pistons from "Big Red" and 5 ltrs of brake fluid DOT4 although the handbook say's DOT3. DOT4 is compatible with DOT3, but has a higher boiling point, and is less likely to absorb moisture. The brake fluid is something I forgot to order with all the other fluids to start with.

Tomorrow I will strip the front offside brake to see what I find Then on to the rears, and possible seizing slide pins.

John.

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Timely intervention it seems John.

I recently changed the front pads on my old IS for my friend, which demonstrated to me how much I miss tinkering with cars.

I just need to convince the misses to allow me to get another car to play with :smile:

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I forgot to say I also added two cans of STP engine flush, and ran the engine as the instructions. Iwill however run the engine daily until I do the oil change to make sure I get as much of the oil lacquer out of the engine.

John. 

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4 minutes ago, Shahpor said:

Timely intervention it seems John.

I recently changed the front pads on my old IS for my friend, which demonstrated to me how much I miss tinkering with cars.

I just need to convince the misses to allow me to get another car to play with :smile:

Working on my car, and my wife's Aygo is one of my ways of staying sane while looked down.

John.

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Let us know how you get on with the piston kit John. I have a piston stuck solid, tried everything to move it (still on car) and not a jot. The other 7 pistols were all in bad shape, with 3 more seized (inner pistols I think on both sides) that I managed to free off and clean up.

This was having failed mot on disks, so I fitted new discs and pads, but needed to use a grinder to cut the pad down on the inner drivers side (the one with piston stuck out) to get the pad in, took about 60% off it 😬. Passed the mot 🙄 and then again the next year 🙄🙄.

I have since got a set of used calipers and will send them off for a complete refurb and paint, then swap both calipers. Just a struggle to find time / money and not been in a rush given that even with that piston not working, she still brakes better than I'd expect. Seems the calipers are a weak point if not looked after (mine were knackered when I got her from previous owner).

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3 hours ago, Upex said:

Let us know how you get on with the piston kit John. I have a piston stuck solid, tried everything to move it (still on car) and not a jot. The other 7 pistols were all in bad shape, with 3 more seized (inner pistols I think on both sides) that I managed to free off and clean up.

This was having failed mot on disks, so I fitted new discs and pads, but needed to use a grinder to cut the pad down on the inner drivers side (the one with piston stuck out) to get the pad in, took about 60% off it 😬. Passed the mot 🙄 and then again the next year 🙄🙄.

I have since got a set of used calipers and will send them off for a complete refurb and paint, then swap both calipers. Just a struggle to find time / money and not been in a rush given that even with that piston not working, she still brakes better than I'd expect. Seems the calipers are a weak point if not looked after (mine were knackered when I got her from previous owner).

To move the seized piston I left the disc pad in on the opposite side, and a block between the other moving piston, and the disc. Then with the car in ready mode to get brake assist I pushed the brake pedal until I felt the piston move.
I cleaned up as best I could the rust off the side of the piston with it still stuck in the caliper but protruding, and painted it with brake fluid to lubricate it.
I then removed the caliper leaving the hydraulics connected, and used a nut, and bolt (19 mm spanner size) and a piece of steel tube about 2" long that fitted over the bolt. This tube fitted inside the stuck piston with the nut screwed up against the bolt head with the protruding thread inserted over the threads, and against the opposite piston with a piece of flat steel over the end of the piston. Screwing the nut off the bolt jacked the stuck piston back into the caliper. 
Doing this a couple of times with a block between the opposing moving pistons to stop them being ejected freed the piston up enough to use if required, but I have left things ready to replace the pistons, and seals as required.
The repair kit from "Big Red" comes with 4 pistons, seals, and dust covers at £35, and I will use one of these saving the others for when problems strike. Working on the principle if it's not broke do not fix it.

John.

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I stripped the drivers side brakes today, and found no problems with seized components so I just removed the lip on the discs, and cleaned them up. This is when I found a problem with the wheel bearing as the disc was spinning through use of the angle grinder on the discs. There was a rotating knocking noise coming from the bearing. One knock per rotation. A new bearing has been ordered to add to the growing list of parts.

Since doing this work I now have a VSC ABS warning, and brake fault lights, but I will clear these after changing the caliper pistons, and flushing the brake fluid.

Tomorrow the rears, and possible sticking slide pins. I know the pads, and parking brake shoes are good having replaced the a year or so ago.

John.

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I can see not only me spend those extra free hours on catching up with car jobs.

I was working today on my wife CRV. Plan was replace rear sway bar bushing. Guess what - last bolt has snapped...

Now I'm in middle of drilling through it but need rotary tool for the last precise bits. Will arrive on Wednesday 🙂 

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1 hour ago, Hangie said:

I can see not only me spend those extra free hours on catching up with car jobs.

I was working today on my wife CRV. Plan was replace rear sway bar bushing. Guess what - last bolt has snapped...

Now I'm in middle of drilling through it but need rotary tool for the last precise bits. Will arrive on Wednesday 🙂 

Waiting for parts does try your patience, but there is always something else to keep you going. I have put the front brakes back together so I can carry on with the rears. Only problem is I know I have to strip them all again.

John.

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Stripped the rear brakes today, and I am happy to say all was good. The slide pins were free, and all that was required was regreasing with the correct grease, the parking brake drums cleared of dust, and after refitting the parking brake adjusted. Before fitting the pads they were cleaned, and treated to some copper slip on the anti rattle shims, and piston mating surfaces. Some copper slip was also applied to the parking brake cable where it exited the backplate. 
The only thing I found was the ball joints on the headlamp leveling system were getting very stiff. These were cleaned and lubricated so that the likelihood of the operating rod snapping is somewhat reduced.

John. 

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Hi John, a quick question about the rear brakes: is it easy to remove & install the piston's dust seal? I'm cleaning the calibers but wasn't sure if I can remove that safely... Any recommendations for the grease to be used with the slide pin?

BR.Sami

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John, that's exactly what I had to do to free my 3 of 4 stuck pistols, bar I used a brake rewind tool and block to push back in. 

4th stuck piston wouldn't move at all, even with days of penetrating fluid (good stuff not universal) and heat, hence got a second set of calipers 🙄

Sounds like you're doing a grand job though, and something good coming out of this unexpected 'free time' I'm locking in at the girlfriends, typical as have a long list of jobs at home, cars and house (in the middle of a bathroom replacement which has stopped completely 😬🙄)

Keep us posted and good luck 😊

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44 minutes ago, Upex said:

John, that's exactly what I had to do to free my 3 of 4 stuck pistols, bar I used a brake rewind tool and block to push back in. 

4th stuck piston wouldn't move at all, even with days of penetrating fluid (good stuff not universal) and heat, hence got a second set of calipers 🙄

Sounds like you're doing a grand job though, and something good coming out of this unexpected 'free time' I'm locking in at the girlfriends, typical as have a long list of jobs at home, cars and house (in the middle of a bathroom replacement which has stopped completely 😬🙄)

Keep us posted and good luck 😊

If piston is stuck you need to get it out rather than push it back 🙂 Most often they stuck due to corrosion so you need to clean it if possible or replace a piston. Most probably new set of seals also will be needed.

Best method I know to remove stuck piston is comprised air. But be careful as piston might come of as a bullet so you must use wood or similar avoid it.

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3 hours ago, Sami Tilander said:

Hi John, a quick question about the rear brakes: is it easy to remove & install the piston's dust seal? I'm cleaning the calibers but wasn't sure if I can remove that safely... Any recommendations for the grease to be used with the slide pin?

BR.Sami

Hi Sami.
I used soap based grease for the slide pins.
As far as the dust seal goes these are made of very thin rubber, and over time they perish. This makes removing them without damage very difficult, but not impossible. Seal kits are very cheap, and I would advise buying some, and replacing them anyway. Bigg Red at Worcester are very good, and speedy at delivering caliper parts or even repairing calipers for you.

John.

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38 minutes ago, Hangie said:

If piston is stuck you need to get it out rather than push it back 🙂 Most often they stuck due to corrosion so you need to clean it if possible or replace a piston. Most probably new set of seals also will be needed.

Best method I know to remove stuck piston is comprised air. But be careful as piston might come of as a bullet so you must use wood or similar avoid it.

I find using the cars hydraulic system or a grease gun filled with brake fluid, but grease or oil can be used if the caliper is thoroughly degreased afterwards. This way you have much greater pressure than most air compressors will supply, and oil does not compress meaning you have much better control over how much the piston moves, and the speed of ejection.

John.

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3 hours ago, Britprius said:

I find using the cars hydraulic system or a grease gun filled with brake fluid, but grease or oil can be used if the caliper is thoroughly degreased afterwards. This way you have much greater pressure than most air compressors will supply, and oil does not compress meaning you have much better control over how much the piston moves, and the speed of ejection.

John.

I wouldn't be too happy about pumping in oil or anything else beyond air/brake fluid.

As for using car hydraulic I don't like it as you will end up with some splash when piston jumps out. As you probably know brake fluid is very aggressive to paint so you might end up with damaged worth more that new calliper early 🙂

My last stuck piston was few years ago on my 2009 Honda Accord. Compressed air with wooden cushion on the other side was good enough. If you got a very stubborn case and need more than 10 bar then you could try to use car hydraulics. From my experience though it was never necessary.

As for grease gun, maybe it is just mine but I doubt it will put any significant pressure and for sure not more than 10 bar.

 

 

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2 hours ago, Hangie said:

I wouldn't be too happy about pumping in oil or anything else beyond air/brake fluid.

As for using car hydraulic I don't like it as you will end up with some splash when piston jumps out. As you probably know brake fluid is very aggressive to paint so you might end up with damaged worth more that new calliper early 🙂

My last stuck piston was few years ago on my 2009 Honda Accord. Compressed air with wooden cushion on the other side was good enough. If you got a very stubborn case and need more than 10 bar then you could try to use car hydraulics. From my experience though it was never necessary.

As for grease gun, maybe it is just mine but I doubt it will put any significant pressure and for sure not more than 10 bar.

 

 

I think you will be amazed at the pressure of hand operated grease guns mine is rated at 340 bar or 5000 psi. 
If you use air to blow the pistons out this will also blow any residual fluid over your paintwork. With fluid as the pressure medium as soon as the piston leaves the seal the pressure has gone. With air this is not the case. This is why pressure vessels are tested with liquid "usually water", and not air. If the vessel fails with liquid it just cracks. With air it explodes. A rag placed over the caliper will catch any fluid.
As far as grease or oil is concerned I did state this should only be used if the caliper went through a degrease afterwards.

One of the things that I noticed on the "Wheeler Dealer" program is that in all the times "Edd" changed brake or clutch master cylinders he would hold the old cylinder over the front wing of the car he was working on with fluid saturated rubber gloves, no cover on the wing, and no warning as to the paint stripper effect that brake fluid has.

John.

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The front hub bearing turned up, and fitting this was my job for the day.
Stripping the brakes, and removing the disk was easy having had them apart a couple of days ago.
Next I removed the four pins that hold the hub bearing to the upright, and disconnected the ABS sensor. Then the fun started there was know way the hub would move from the upright. Eventually I removed the wheel studs simply by knocking them out with a hammer. Then using two of the hub holding bolts with a couple suitable fine threaded nuts I put the bolts through two of the holes in the hub from the outside with nuts fitted on the inside.  A small socket was put over the ends of the threads, and against the aluminium upright. Tightening the bolts jacked the steel bearing hub out of the very corroded aluminium upright.
The rest was just a matter of cleaning up the hole in the upright with a flap wheel so that the new hub bearing was a snug fit in the upright. Reassembly was then strait forward without further problems.
To anyone contemplating changing a hub bearing the biggest problem is the galvanic corrosion that occures between the steel hub, and the aluminium upright. I had much the same problem changing a Prius front hub bearing about six years ago, but with that I had no alternative but to take the complete front upright to a local machine shop, and use there hydraulic press.

I am hoping tomorrow the caliper seal kit will arrive. A 4.5 ltr drum of DOT4 brake fluid arrived today. 

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On 4/4/2020 at 9:39 PM, Hangie said:

I can see not only me spend those extra free hours on catching up with car jobs.

I was working today on my wife CRV. Plan was replace rear sway bar bushing. Guess what - last bolt has snapped...

Now I'm in middle of drilling through it but need rotary tool for the last precise bits. Will arrive on Wednesday 🙂 

Success, I’ve managed to flat the surface of the bolt with rotary. Then made a nice cut for a big flat screwdriver to settle in.

last step was 1kg hammer. I have it few good whack and I’m home. I’ve managed to knock of the whole nut out of the subframe - with the bolt inside of course.

now I just need new nut and bolt, I’m going to buy stainless steel to avoid similar issues in the future.

 

 

 

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Today as hoped on the dot of 10 am the postman bought my caliper repair kit from Bigg Red. Fitting was the order of the day.
After removing the the nearside front wheel I then removed the inner brake pad. It was the inner lower caliper piston that was seized because of a hole in the dust cover letting in water.
After blocking the top piston I operated the brake pedal till it went hard. Checking the caliper I found the seized piston had been pushed up to the disc.
I then removed the two caliper holding bolts and put a wood block between the upper two pistons.. After clamping the brake hose I put a "G" clamp onto the lower outside piston, tightening the clamp. This pushed that piston in and the inside piston out.
Cleaning up the caliper bore with some paper towels I inspected it, and found that the inner bore behind the seal to be in very good condition. The outer bore to the outside of the seal was rusty in places as was the piston. I cleaned up the outer bore with emery paper then hooked out the seal. I then thoroughly cleaned the area around the piston entry including the grove where the dust seal fits. Then washed it with brake cleaner blowing away all the fluid, and dirt with compressed air.

After lightly greasing the new seal with the grease supplied I fitted it in it's groove. Then the new piston was give a wipe with brake cleaner, and a fresh paper towel then greased with the same grease. After slackening the bleed nipple i pushed the piston into the caliper bore feeling it entre the seal, and push all the way home. The dust seal was then greased, and fitted over the end of the caliper piston, and then over the groove in the caliper it's self.

I then refitted the caliper, and disc pads. After removing the brake hose clamp I found the brakes bleeding themselves by gravity so I fitted a hose to  the bleed nipple, and into a jar. I then topped up the brake fluid in the container. When I was sure there were no more air bubbles coming from the bleed nipple I tightened it up. After pushing the brake pedal a few time to push the pads up to the disc I had a really good brake pedal.
My intention is to do a brake flush using Techstream in the next few days, but for now the car can be moved around knowing the brakes do work

Some might say why did you not do all four pistons? My answer is the piston seized due to water entering through a split in the dust cover. This then holds the water inside causing rust, and seizing. After inspecting the other three caliper piston dust covers they were found to be in very good order. I then work on the principle if it ain't broke don't fix it. I have three new piston, and seal assemblies in stock that will fit either side of the car should a problem arise. 

John.    

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14 hours ago, Hangie said:

Success, I’ve managed to flat the surface of the bolt with rotary. Then made a nice cut for a big flat screwdriver to settle in.

last step was 1kg hammer. I have it few good whack and I’m home. I’ve managed to knock of the whole nut out of the subframe - with the bolt inside of course.

now I just need new nut and bolt, I’m going to buy stainless steel to avoid similar issues in the future.

 

 

 

I'm not familiar with the particular set up, but in general you shouldn't use stainless steel for suspension bolts - it's not strong enough. All suspension bolts need to be high tensile. Best to buy original manufacturers parts for suspension applications or anywhere that is under stress.

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4 hours ago, johnatg said:

I'm not familiar with the particular set up, but in general you shouldn't use stainless steel for suspension bolts - it's not strong enough. All suspension bolts need to be high tensile. Best to buy original manufacturers parts for suspension applications or anywhere that is under stress.

I was about to submit a post along the same theme. After re reading Krzysztof's post realized the bolt concerned only holds the "U" bracket over the "D" shaped rubber mount, and is not a critical or high loaded component. However erring on the side of safety is never a bad philosophy.

John. 

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2 hours ago, Britprius said:

I was about to submit a post along the same theme. After re reading Krzysztof's post realized the bolt concerned only holds the "U" bracket over the "D" shaped rubber mount, and is not a critical or high loaded component. However erring on the side of safety is never a bad philosophy.

John. 

I wouldn't use those for anything like control arm mounting but as John has stated it just hold "U" bracket which then hold rubber. There is not significant force put on those bolts.

Using stainless steel wasn't about saving as those are even more expensive. I've done this trick before and never got any issues with it. Of course in case of some horrible bad luck even if bolt will fail nothing major will happen and should be easy noticeable with knocking sound.

PS. I've only replaced a single bolt anyway 🙂

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I did a front to rear service on my wife's 2006 Aygo today at 76,000 miles.
I stripped the brakes front, and rear, changed the oil, and filter, changed the air filter, plugs, AC filter, flushed the brake fluid, changed the gear oil, and reset the clutch adjustment with Techstream  "MMT version automatic". Things were so easy to do, and there being no problems what so ever I was finished by lunch time. This car amazes me as after 14 years everything on the car still looks near new, and works.

I then decided as I was on a roll I would change the plugs on the GS450H. This turned out to be easier than at first it seemed. A couple of the plugs were alarmingly tight even after they started to turn, but a little WD40 down the plug holes, and turning back, and forth soon got them freed. After removal they still look in very good condition with the gap still well within tolerance, and virtually no carbon build up. I do not know how many miles they have done. I have done 60,000 miles in the car, and have never changed them. They were still fit for many more miles.
Next job is the engine coolant pump, and antifreeze change then engine oil "with 0w16 oil", and filter. When this is completed If I can manage lying on the ground I am going to change the transmission oil pump bearings.

John. 

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