Brake System Maintenance Question

[D.FYLAKTOS]

 

Some guys use the:

 

[Thefeliciahacker]

Yes it's absolutely fine 

[nta16]

Just an example Pagid CERA TEC - 

"Cera Tec is for lubrication on metal-metal applications such as Caliper sliders.

Ideal for the lubrication disc and drum brakes, compressors, central lubricating systems, axle bearings, chains, seat tracks, sunroof guides and battery contacts, the perfect compliment for Pagid brake parts."

 

It may or may not help with that brake squeal you mentioned.

 

Not to be used with slide pins on rubber 

[R_Blue]

I have some good news and bad news.

 

Good news first:

I've dealt with the worn clutch pedal guide pin and its OK now.

 

 

 

I found a half threaded bolt which has (roughly) 6.1mm non-threaded section and I pressed it in after removing the old pin.

Then, I drilled a hole for a cotter pin and cut the excess of the bolt. I've placed washers on both sides to ease side friction.

 

Now, the bad news:

I've checked the condition of the front brakes and learned that flexible hose renewal is at the bottom of the list.

 

When I got the car, front wheel bearings were bad. At that time  I didn't have all the tools to remove the front hub carrier to make the job so I had to take the car to the mechanics. At that time, I had also provided new discs and pads so they can be renewed too. I also told them to tend to the guide pins and their rubber boots too. They told me that, there was a modification in the calipers done before but I didn't know what was the modification. They told me it was OK. They were leaving it that way by only replacing the boots.

 

Now I saw what happened.

 

- First, all rubber boots, (Right and left. 4 pins the same) had been attached only from one side. (WTF???) Their purpose had been destroyed this way.

- I've found general purpose yellow calcium grease residue.

- Guide pins' rubber boots are damaged.

- There is uneven wear on the brake pads. Outer pads on both sides are thinner. Right side is the worst. It is also worn from top. (Top side is thinner than bottom side)

- There are sleeves on the guide pins. (This was the modification they told me) Why there are sleeves on the guide pins? Any ideas? They look like some kind of plastic too. Maybe made from PTFE? To make these sleeves fit, they should have either drilled the guide pin hole larger or made the pin thinner. I don't know.

 

So what to do now? There was only %3 brake force difference at the front wheels at the time of the MOT but there is something wrong here.

I think I have to replace the brake carriers, pins and the boots. Right? (+ new brake pads)

 

[Thefeliciahacker]

Well they bodged it bad, usually the guide pins ware out therefore develop slop and rattle when going over bumps. 

Still can be bought new and from high quality manufacturers. 

Tonight I'll measure mine which I replaced to see their diameter, then measure both the carrier and the pin itself. 

See what they messed with, sadly that a VERY critical safety item, I've seen caliper carriers snapping off because of excessive slop. 

You do not want that, I guess you were lucky with those measurements at the mot center, most likely, the pads were not work enough to cause binding of the guide pins. 

Here is a link for the pins. 

 

https://m.autodoc.gr/bosch/12792477

Edited 16 April, 2023 by Thefeliciahacker

[R_Blue]

1 hour ago, Thefeliciahacker said:

Well they bodged it bad, usually the guide pins ware out therefore develop slop and rattle when going over bumps. 

Still can be bought new and from high quality manufacturers. 

Tonight I'll measure mine which I replaced to see their diameter, then measure both the carrier and the pin itself. 

See what they messed with, sadly that a VERY critical safety item, I've seen caliper carriers snapping off because of excessive slop. 

You do not want that, I guess you were lucky with those measurements at the mot center, most likely, the pads were not work enough to cause binding of the guide pins. 

Here is a link for the pins. 

 

https://m.autodoc.gr/bosch/12792477

What's happening with my case is, I'm rebuilding the car part by part. 🤣

I've got used to that. From my first repair, until this last discovery, same story again and again.

There are few sections which I haven't "touched" yet. Like interior parts of the gearbox and the engine. I wonder what perils await me in their darkest depths. 🤔

 

I've measured the thickness of the pin with and without its sleeve.

With sleeve: 10.6mm

Without sleeve: 8.25mm

Edited 16 April, 2023 by R_Blue

[nta16]

18 hours ago, R_Blue said:

There was only %3 brake force difference at the front wheels at the time of the MOT

I took that to mean there is 3% difference from one side to the other but that could be that both sides are braking well, poorly or in differently, with the 14% on the rears one side isn't working as well as the other  - is that not what the % difference means?

 

[R_Blue]

3 hours ago, nta16 said:

I took that to mean there is 3% difference from one side to the other but that could be that both sides are braking well, poorly or in differently, with the 14% on the rears one side isn't working as well as the other  - is that not what the % difference means?

 

Yes.

They measure the brakes as "axles" and calculate the variation between two tires on the same axle. If it's too much, that means the car will drag to the sides when braking. It won't be safe so it can't pass the MOT. I think there must be a minimum braking power value too.

 

[Thefeliciahacker]

12 hours ago, R_Blue said:

With sleeve: 10.6mm

Without sleeve: 8.25mm

So the carrier is it drilled out? 

[nta16]

10 hours ago, R_Blue said:

They measure the brakes as "axles" and calculate the variation between two tires on the same axle. If it's too much, that means the car will drag to the sides when braking. It won't be safe so it can't pass the MOT. I think there must be a minimum braking power value too.

Thank you, I thought that was the case.

 

I was surprised to see the the average brake force of the front and average of the back were almost exactly the same but that is good but I don't know how it was measured, we have two or three systems over here.

 

But as you have found these figures do not tell the whole story.

 

Sorry for the distraction.

 

[R_Blue]

8 hours ago, Thefeliciahacker said:

So the carrier is it drilled out? 

Actually I was waiting your measurement and gave the numbers in advance. After a quick search, I think normal pin diameter is either 8.1 or 8.3mm. According to what I've measured, looks like they drilled the carrier like you said.

So, I need a new caliper carrier set.

I saw this item listed as a set from some local dealers. Including the caliper carrier, pins, rubber boots and even the grease. (Checking availability right now)

 

4 hours ago, nta16 said:

Sorry for the distraction.

You are welcome.

 

----------------------------------------------------------------------------------

I'm still gathering parts and bits.

I have a liquid thread locker.

I've visited some grease sellers about the caliper pin grease you have mentioned above and they had no idea. They told me that mechanics use "normal grease".

On-line searching, I've found Bosch Superfit TO100 or general purpose silicone grease.

If the new pins won't come with a bundled grease pack, I'll order one of these.

 

The bolts also seem old.

They are listed as, M10x45x20 (half threaded) for the caliper carrier and

M8x21 for the pins.

Both set are 10.5 or 10.9.

 

I have new bolts but they are rated 8.8. I think, I should search for 10.9 right? Because they play a critical role here.

[Thefeliciahacker]

21 hours ago, R_Blue said:

 

Sorry m8 holidays I'm heading right now 

[Thefeliciahacker]

The bosch set that I used came with white (aka lithium) grease I don't like it tbh as it causes rubber to age. 

A very good idea is marine grease, silicone as well, Calcium is also Okey. 

10 minutes ago, R_Blue said:

10.9

Don't you dare use 10.5

[Thefeliciahacker]

10 minutes ago, R_Blue said:

8.8

Will yeild at 640 mpa

10.5 will yeild at 500mpa

10.5 to me is a stretchy bolt, something I would use in a tty situation. 

Mind you these are TENSILE strength numbers, shear strength is about 50%-60% of tensile .

[R_Blue]

11 minutes ago, Thefeliciahacker said:

Sorry m8 holidays I'm heading right now 

 

9 minutes ago, Thefeliciahacker said:

Don't you dare use 10.5

 

5 minutes ago, Thefeliciahacker said:

Will yeild at 640 mpa

10.5 will yeild at 500mpa

10.5 to me is a stretchy bolt, something I would use in a tty situation. 

Mind you these are TENSILE strength numbers, shear strength is about 50%-60% of tensile .

One of the old ones had 10K written on it. So it's either 10.5 or 10.9 I think.

Your advise is to use 10.5 right?

[Thefeliciahacker]

There you go 

[R_Blue]

20 minutes ago, Thefeliciahacker said:

There you go

I'll definitely buy a new caliper carrier & pin set.

Thanks for the help.

[Thefeliciahacker]

1 hour ago, R_Blue said:

Your advise is to use 10.5 right?

NO absolutely not

[R_Blue]

On 17/04/2023 at 17:59, Thefeliciahacker said:

NO absolutely not

Sorry for the typo. I was going to write 10.9.

 

Here is the new set of bolts but there is one more problem now.

They told me that it was very hard to find new M10x45x20 10.9 bolts. So I have regular M10x45.

I know the not-threaded part of the bolt is there to provide extra strength.

I don't know how the old bolts will come out or they had been replaced before.

 

Would you use the old M10x45x20 (Half threaded, original 30yrs. old bolts)?

or new regular M10x45 10.9 ?

[Thefeliciahacker]

Use them the bolts are perfect except if you want me to try and find you some bolts 

Edited 19 April, 2023 by Thefeliciahacker

[R_Blue]

You know, I was going to make this maintenance work. Maybe you won't believe me but, when driving downhill in the morning the car greeted me with a blinking brake warning light. That particular light wasn't working when I bought the car. I'm glad I fixed that.

I already knew, the front brake pads were thin so I thought it's normal to have lower fluid level after some point, but it's worth checking right?

 

There was no sign of leak visible anywhere. As a part of the maintenance, rear drums were going to be opened. So it seemed logical to check them first.

 

When I opened the rear drums, there was a nasty surprise for me.

First picture is from two years ago when I renewed rear brakes.

 

If you look closer, you will notice damage on the paint. That means the cylinder was leaking.

 

Also check this out:

 

 

This was rear right.

Rear left had a worse leak than this.

 

 

Now why did they leak only after two years? Both wheels?

 

So the work started with these.

 

As you can see on the left side, the leaking fluid came into contact with the bearing seal. As a result, bearing seal was compromised. Inner side of the bearing got stuck on the stub axle. Some of the grease was escaped into the drum too.

I had to remove the stub axle.

As a result of the removing process, the bearing became unusable.

I bought a new bearing set. Removed the old ones, and installed the new set for the left wheel.

I cleaned the brake carrier plate. My previous paintwork was ruined. Due to the time constraints, I couldn't paint it this time. But I left a thin oil coating on the surface.

I also lubricated the friction points on the brake carrier plate with special brake grease.

I cleaned the brake pads with brake cleaner.

 

Their thicknesses are well within specs.

 

I also bought two new brake cylinders and replaced them on both wheels.

I replaced the 8.8 stub axle bolts with 10.9 s.

Brake cylinder bolts (M6x10 inbus) were rusty. I replaced them with A2-70 grade inbus bolts.

 

Drums on both sides were OK.

 

I replaced bearings and the gasket on the left side.

I replaced the gasket on the right side.

I wiped old grease as much as I can and renewed the grease.

I cleaned the friction surface on the drums with brake cleaner.

I reinstalled the drums and adjusted the retaining nut accordingly.

 

 

Conclusion of day one.

 

 

 

Edited 27 April, 2023 by R_Blue

[Thefeliciahacker]

Oh my god, luck is not on your side, sometimes... 

[nta16]

51 minutes ago, R_Blue said:

Now why did they leak only after two years? Both wheels?

I would guess the brake cylinders may have been either a rare failure or their manufacture was very poor and/or they might have included ****-poor rubber seals.

 

On the Midget I had a about 2 years or less old rear wheel slave cylinder go overnight whilst the car was parked at a national show, great to see as I arrived first thing in the morning and meaning no more passenger rides for donations to charity.  I have got rid of my records now and I cannot remember if this wheel cylinder failure only happened the once, other ****-poor rubbish rubber products certainly gave repeated failures when trying different general suppliers.

 

With "classic" British car parts buying any modern made part with rubber in it at the time was a gamble at the time even if it was from an old manufacturer name with a good reputation as companies or their names are sold and the new products manufactured completely elsewhere using lower quality materials and manufacturing.

 

With the Midget you could buy 'repair kits' for the wheel cylinders but as these are just rubber seals and very mostly 'aftermarket' so you were on the same gamble.  I do not know but quality of these parts may have improved purely by the large turnover of parts stock and perhaps complains or the ****-poor rubber products were used up as they would be replaced at a rapid rate.

 

If you have bought exactly the same wheel cylinders again from the same batch of manufacturing then you might, or might not, get the same results.

 

Have you researched the brand the of wheel cylinders you have bought, sometimes it is best to pay more and get good brands from (brake) specialist suppliers rather than general parts suppliers.

 

Hopefully you have better luck this time.

 

[R_Blue]

Second day:

 

I had already found new (but old stock. dated 2011) caliper carriers several days ago and already painted them for the upcoming work.

 

Before the work:

 

 

I replaced caliper carriers on both sides.

Like with the many aftermarket parts before, one of the caliper carriers refused to fit. I had to modify it a little bit. I also filed the edge of the caliper carrier mounting part. I applied paint to these places before mounting them for the final time.

 

 

I replaced flexible hoses on both sides and of course fitted new brake pads.

 

After the work on the front section:

 

After this, the hard part came.

Rear flex hoses are, as you know, placed in a very hard to reach place. Especially if you have to work on the ground.

I applied WD40 to the brake hose unions.

 

 

I know, from this point of view, just looking at the picture, it looks easy. But it's not...

 

I don't know why but unfastening these joints was a real pain in the a.s. Quite literally.

Both the unions and the spring retaining clips were stuck.

 

After the work here:

 

After completing the work at this section and before lowering the back side of the car;

I removed and cleaned the brake fluid reservoir.

After attaching it to it's place, I filled it with new brake fluid and started the bleeding process from rear right wheel. After that, I passed to the rear left.

I installed the road wheels, adjusted the hand brake and lowered the rear. Thus, completing the work on the rear.

I continued the bleeding process. Front right first. Lastly front left.

 

I lowered the car and checked for leaks. After that, I went for a road test.

Because of the run-in period of the new pads, the brakes were a little bit weak at first but I know that's normal.

After the short trial, I checked again and there was no leak.

 

Conclusion of the work at the end of day two.

[D.FYLAKTOS]

You could paint the calipers with another ''fancy look'' colour (heat resistance).

They look good with the (aluminium colour) rims.