Wheel Cylinder Repair

[coopns]

02 Caravan. Last week was out and stopped to get gas and I noticed some vapor from back wheel, peeked under and saw brake fluid splattered around tire area. A mech came out and had a quick look and figured it was a wheel cylinder, it was Sat. and said would be fine for a week, would probably just weep. And it has. So I got the cylinder. I am not shy about taking a crack at it but don't want to get too far over my head.

Any advice/recommendations? Any special tools?

 

[AandPDan]

Pick up a new set of shoes too. Your going to have to replace them, both sides.

Do you have a helper to bleed them?

It's not that difficult a job. You might want to spray some penetrating oil where the line attaches to the wheel cylinder. Make sure to use a brake wrench so you don't round the fitting over.

Good luck.

 

[exranger06]

You'll need to remove the shoes to replace the cylinder. If the friction material got wet, you should replace them. I would jack up the rear of the van and remove both wheels and drums. You'll probably forget how some things go back together, so look at the other side as a reference. A pair of spring pliers can be useful. And you'll of course have to bleed the brakes when you're done.

 

[coopns]

Is it a must to replace the shoes? I don't know if this is a factor but will be selling the car to dealer in Jan. But breaks are breaks, need them to work correctly. Just wondering.

Thanks.

 

[Donald]

You could wait and have a look. If excessively worn or brake fluid got on them, they should be replaced.

You can repair the wheel cylinder with a kit and a hone. Take a pic of the wheel once the hub is off so you know how things go.

If you replace shoes on one side, do the other.

You should have a tool to adjust the star adjusting wheel, but can make do with a large screwdriver usually. If the drum does not come off it could be the star adjustment wheel needs to be backed off.

 

[AandPDan]

Originally Posted By: coopns
Is it a must to replace the shoes? I don't know if this is a factor but will be selling the car to dealer in Jan. But breaks are breaks, need them to work correctly. Just wondering.

Thanks.


Any fluid will contaminate the lining. It depends upon how bad the leak was. I've seen some so bad that the shoes actually fall off the backing.

 

[Kruse]

Originally Posted By: coopns
Is it a must to replace the shoes? I don't know if this is a factor but will be selling the car to dealer in Jan. But breaks are breaks, need them to work correctly. Just wondering.


For the safety of the driver and the passengers, replace the brake shoes. Also get the drum clean and free of brake fluid. I know a guy who was so tight that insisted on spraying the shoes with brake spray to get the brake fluid out. It took about six cans of brake spray before he gave up and bought new brake shoes. If you can see the brake fluid coming out of the drum, it's soaked into your brake shoes.

 

[mechtech2]

Do you want to repair the cyl as in the title post or replace it?
I recommend a replacement.
If a line won't come off, get a replacement . Cut the line flush and use a 6 point [pref flank drive]socket.

 

[punisher]

If there is brake fluid on the shoes, they are to be replaced. Not even a choice.

A line wrench is often handy, and depending on what holds the cylinder to the backing plate (if a clip) then a prybar/visegrips to pop the clip out. If it is bolted to the backing plate, lucky you.

 

[coopns]

I'm sure there is fluid all over the brakes, it was fairly damp.

I just got some new shoes and a spring kit. Got it for 50. I need the rig for another 3 months (4 kids/complaining wife) to cart around so I don't mind.

Just curious, why if brake fluid gets on the shoes are they toast? Does it break down the shoes?

 

[Kruse]

Originally Posted By: coopns

Just curious, why if brake fluid gets on the shoes are they toast? Does it break down the shoes?


When the shoes are soaked, there will be no brakes because the shoes have no friction. When the shoes start to "dry out", the shoes will grab. When they finally do dry out, they will glaze over and you will again have no friction, or in other words, no brakes.

 

[Silk]

Brake fluid is not oil, it's water soluble. Clean and soak in hot water. Dry, deglaze and repeat a few times. If you can still see contamination coming through they should be replaced.

 

[mattd]

wheel cylinders both sides, and a set of shoes and hardware. Torches for the brake lines if you can.

 

[Stu_Rock]

Originally Posted By: Silk
Brake fluid is not oil, it's water soluble. Clean and soak in hot water. Dry, deglaze and repeat a few times. If you can still see contamination coming through they should be replaced.
I agree, especially if it's mild contamination. I have put contaminated shoes back into service after a water wash, and they have worked 100% fine.

Mine were riveted semimetallic shoes, so I can't comment on the effect of contamination on bonded shoes or those made of other friction materials.

That said, I always had another car to use while I washed the shoes and let them dry. If I needed to get the car back on the road quickly, I'd just go for new shoes since they're usually cheap.

 

[mechtech2]

If shoes have been wetted, sometimes they can be saved. Brake cleaner, or carb cleaner can get them pretty clean.
Depends on how long and how much.
Sometimes I have used a torch to burn out fluid, then clean and sand them.
Sometimes you have to use unorthodox methods.

But of course new shoes are always correct.
Note that brake shoes take a LONG time to seat in. After 20,000 miles, they still may show areas of no contact.

 

[coopns]

Ahhhh! Mad. So I had a min (4 kids played...wife was taking a brake) so I jacked it up wheel off, one screw in the back and disconnected brake line. Easy enough. The cylinder was sandwitched in between two brake parts at the top. So I wedged those two metal pieces that hold the cylinder together and it kind of came out. I wasn't sure how much to force it, those metal springs pieces were moving around pretty good.

The cylinder looked like it was welded on there but couldn't be right? Looked like there was some type of sauter type holding it on there but must not have been. So should I have just cracked the cyl. with a hammer to loosen it up?

Ran out of time (kids and wife) so I just put it back together added some brake fluid and now it doesn't stop very well petal is really spongy. It was pretty messy. I did spray some carb cleaner on the drum and around brake parts. Again, I have new shoes/cyl. so will be using those. Last time I did the drums was about 4 years ago so bit nervous to get into that.

 

[yonyon]

When you disconnected the brake like you replaced some of the fluid with air. Air is compressible, so there's your spongy pedal. Your brakes are now very unbalanced and you should not drive this vehicle until you bleed the brakes unless it is absolutely necessary in an emergency situation. Expect emergency stopping distances to be very bad and if the roadway is wet you could easily go into a 4 wheel skid.

I'm pretty sure there are two bolts holding that wheel cylinder on, not one.

By emergency I mean: one of your family members requires immediate medical attention to prevent permanent disfigurement or death.

Emergency does not mean: I ran out of mint chocolate chip ice cream.

 

[coopns]

Update: Not that you care but I had to tell someone (right...wife doesn't care).

So I figured without doing the shoes (which I was aprehensive about) I could/should be able to do this. Carb Cleaner all over, sand paper on drum. Took the two screws off the back, disconnected brake line. Put the new cyl. back on and I haven't bled brakes at the line before (I was the one on the petal). Wasn't bad though, had the wife pump and I had the bleeder screw. It spit out some air and bubbles but I had her pump 3 times and fluid was coming out (clear). Was that enough/right?

Buy me some time anyway. I will keep the shoes. Should I have made any adjustments to the spings?

Thanks for all the suggestions/advice.
Quick spin and petal felt tight.

 

[yonyon]

As others have already stated, the shoes should have been replaced. They may not provide as much friction now as they did before.

Assuming you're just not going to replace the shoes at this time, it would be a good idea to pull the drum back off and dump a nice big buck of water on there to thoroughly rinse everything. Also rinse the drum thoroughly with water. This will remove more of the old fluid than you were able to get rid of with brake cleaner. Brake fluid makes things rust. Rinse the back side of the wheel cylinder as well so that after a few days you can check for any seepage where the line screws in.

Keep an eye on the other side for a while. It's pretty common for original wheel cylinders to fail within six months or so of each other.

 

[The_Jeff]

You want to adjust the adjuster, it's the whatsamajigger with thread that spreads the shoes. The redneck way of doing it is you probably have a ridge on the inside lip of the drum, that ridge should barely shove over the shoes then you can seat the drum fully and spin the drum and just sort of hear it scraping on the shoes a little.

Also, check the left rear metal line. They rust out first, and fast, on those vans.