MR2 MK2 sill repair - cheap panel!

[Pigeon_Droppings2]

Yea I tend to agree...I think the piston has probably corroded slightly and is sticking. Easy enough to just remove and clean it up...of course it's even easier to drive it around for a few weeks in the hope it goes away on its own

 

[Pigeon_Droppings2]

Well I drove the MR2 yesterday after a few months...drives faultlessly except for the brakes. Now that I know the caliper is sticking I have to sort it out....even though I can't tell by driving it!

The rev1 MR2 originally had 14 inch wheels...later models got 15 inch wheels and bigger discs. There is lots of discussion about there being no difference in brake performance...but I need to sort the calliper out anyway so it seems like the perfect opportunity to also upgrade to the bigger brakes.

Managed to source a set of front brakes from an mr2 turbo on fleabay. I was expecting the worst but actually the pads and discs were brand new. I need the full set as I needed the calliper holders...the holders on their own seem to go for £60 a pair so getting the complete set for £100 was a bargain. They are actually in nice condition with all the correct springs and clips.

First step was to strip them down, block up the fluid hole and send them for a citric acid bath. I know there is a lot of discussion about damaging rubber parts with citric acid...in this case I'm rebuilding the brakes with new seals so doesn't matter. The main reason for the soak is that I want to loosen up the corrosion....plus I'm hoping it will mean that I can get the bleed nipples out without breaking them....fingers crossed.

 

[RaceDiagnostics]

If you have a cup boiler to heat the solution it will be much more effective than ciold.

 

[Pigeon_Droppings2]

I did 10 kettles of boiling water ....agree though it would be a lot better with a heating element.

 

[Pigeon_Droppings2]

Well I spent most of the holiday ill....very annoying indeed. Just getting back into things...managed to get both sets of calipers cleaned up. When they came out of the citric acid they looked a strange bronze colour...which did confuse me a little...then I remembered I had been using a bronze bristled brush to agitate them so all explained.

Next job will be to give them a good going over with a wire brush and then paint them. I managed to pickup the rebuild kit from BigRed so all good to go on that front. The pistons were a little scored so I decided to replace them too...just not worth the hassle vs small cost of replacement.

I ended up having to redo the citric acid...the rust was actually stuck under a layer of black paint so I had to scrape the paint off first in order to let the acid do its work.

 

[Pigeon_Droppings2]

Several hours with a drill and wire wheel...wish I had a blasting cabinet!

At this point I kind of wished that I had just bought a refurbished set of callipers...but that would have set me back £250 easily...then I'd still have needed a pair of discs and pads plus a set of carriers so reckon I would have been in for £500 at the end of that road.

Spend so far has been £100 and around £40 for the rebuild stuff as I also bought new pistons and new pin sliders etc.

 

[Pigeon_Droppings2]

Then finished with 2 coats of high temp paint....I thought of doing them in gun metal grey but that would have meant buying a new tin of paint...I had the silver paint left over from when I did the mr2 engine heat shields so it was "free" in a sense. The paint will need baking or some spirited driving to activate the heat resistance as it needs to get up to 90 degrees C for about 30 mins. I may just drive the car as that will be easier...I can imagine getting in a lot of trouble if the missus catches me with these in the kitchen oven!

I refitted the old piston seals for the painting and blocked up the piston holes...the groove at the top is for the dust seal so not so important whether paint gets on that. Next job will be rebuilding the insides. This is my first caliper rebuild....I'm actually very surprised how simple the mechanism is....just a simple piston and a single fluid rubber seal and then a dust cover.

 

[Pigeon_Droppings2]

Pdg...totally agree....I thought about using a heat gun but it would be difficult to keep the temp consistent plus they need 1.5 hours a piece! Instead I bought myself a cheap electric oven for the garage...£45 well spent I think. Checked the temperature with laser thermometer and it's actually not bad Vs the dial.

Calipers need 3 bakes for 30 mins each time at progressively higher temps...with 30 mins rest in between which is quite handy as I'm doing them in batches....one set in the over and one set resting.

So bake for 1.5 hrs total per set or until golden brown and cooked through .

 

[Pigeon_Droppings2]

Yea I've always just made do up to now but with the calipers I wanted to do them properly. pdg, do you/can you use yours for powder coating bits too...I remember doing powder coating at school and always wanted to give it another go as its very handy.

I got the "mini" oven purely because I'm limited on garage space...totally agree I think it's going to come in very handy. I'm probably going to end up upgrading to a bigger one eventually...thanks for the oven suggestion.

Lesson number 1....it would have been a lot easier to have a bigger oven and be able to hang the parts inside....grrrr!

 

[slim_boy_fat]

Obviously need a booth of some sort to apply the powder too.

Cardboard box?

 

[Pigeon_Droppings2]

I've got a perfect spot I could use in the garage for the powder spraying . Here are the finished calipers...took me about an hour to replace all the seals as the dust covers are a bit fiddly. I used BigRed for all the bits...I fitted new pistons as these are calipers that I don't know the history. If I was just rebuilding an existing set and I knew there were no leaks I'd probably have just changed the seals.

Only problem is the discs now look a bit shabby so I think I'll clean them up too before fitting.

These came out quite well...would definitely do it again although there is a technique with those dust seals. I found it easiest to fit the disc seal to the piston and then slide it half way in....then carefully ease the lip of the dust seal into position in it's groove followed by the spring clip.

 

[slim_boy_fat]

^^ Nice work, looks as good as new!

 

[Pigeon_Droppings2]

Cheers slim...it's been a nice little side project for me as I can't get down the garage at the moment. I think "next time" I will hang the calipers in the oven...what I noticed is that when baking the paint is very easily damaged as it's very soft....all part of learning something new of course.

I've always just done the exchange in the past but this time I couldn't because the brakes are getting an upgrade so this route made sense + I've always wanted to have a go at doing a set.

Always wanted to rebuild a gearbox too at some point as I reckon that would be a lot of fun....one for the future.

 

[slim_boy_fat]

Years ago,I had a Wartburg [but that's another story ] which I thought needed a new clutch. Removed the 'box to find the clutch assembly soaked in oil which was leaking past a Gits oil seal on the main shaft. Seemples, thinks I.......not so!

Turns out there was wear on the shaft itself, and I so planned to have the wear machined out and a phosphor bronze bush made to fit instead of a fresh/replacement Gits seal. Seemples, again...... The car had a free-wheel arrangement and as I started to investigate, the clip securing the cage turned into a pingfeckit - cue little tinkling noise as half the rollers disappeared into the depths of the 'box. You know that pricky feeling you get at the back of your neck.....

Luckily, more by good luck and a whole lot of inverted shaking, than good guidance, I managed to retrieve them all, but it didn't bode well for a while.

Good luck if you tackle one, I suspect they may be more complicated nowadays than the one I took on.

 

[Pigeon_Droppings2]

I know exactly what you mean....it's funny how a job can go totally wrong in a matter of seconds...at that point I usually walk away and have a cuppa and a good think before I follow up misfortune with a bad decision that makes things even worse!

I almost bought a Volvo V70 with an auto box problem just so I could have a tinker....then thought better of it...well the seller was honest about the gearbox issue...he just forgot to mention the engine oil pouring out of the join between the gearbox and the engine and on a Volvo thats either the engine plug failing or the main crank seal....neither very pleasant jobs to fix!

 

[Pigeon_Droppings2]

Here are the discs...there is zero wear on them...literally no lip at all so I got very lucky I think. Plan is a light clean and then paint the non friction bits. The MR2 does very little mileage so the paint is to try and slow the rust as the rust will prompt a replacement of the discs long before they wear out!

I got the calipers, carriers and the discs and pads all for £100...the original plan was to throw away the discs and pads and buy new ones but when they arrived they were basically new so I decided to just use them too. You can tell they are new as the webbing inside the discs hasn't started to rust yet.

 

[jpmillermatic]

great find on the discs and brake parts!....what a bargain..... nice and usable too from the looks of them.


JP

 

[mike 109444]

If you have got access to a dti might be worth temp fitting disc to see if they run true !