120 and 1800 rear brake shoe fitting

[940_Turbo]

Following on from the half shaft oil seal we decided to pull the drum off again and replace the rear brake cylinders and shoes. The shoes weren’t looking especially spectacular and there was a bit of brake imbalance when the car went in for its re-test. I’ve seen so many 120s with incorrectly assembled rear brakes that I thought I’d share. I even found a how to in the web that finishes with the leading and trailing shoes swapped over... .

The first part is http://www.volvoforums.org.uk/showthread.php?t=108706 it shows the brake drum puller; make no mistake you’re going to need one to pull the rear drums off!

There are a few things to note when doing the brakes.
1) Brakes are safety critical. Please ensure you’re competent to carry out the work. Seek help if you’re in any doubt. This is what I did I cannot ensure that the work YOU do is safe!
2) The brakes on a 120 and 1800 have leading and trailing shoes. It is important you get them the right way round.
3) You can wreck a perfectly good brake drum by installing the woodruff key badly!
4) This is a single line system. If you’re not replacing the brake cylinders peel back the rubber boot and make sure it is dry inside. If it is leaking, the seals are toast.
5) Check the brake cylinders have the same diameter pistons. Estates, non servo and served cars used a different diameter piston. I’ve lost count of the number of cars I’ve seen with odd cylinders!

Mostly the brake adjuster will be seized. If the adjuster will back off it’ll make it easier to get the drum past any wear lip. It is very worthwhile spending a few minutes working copper ease into the thread of the brake adjusters. The adjusters are cheap and readily available. Replace them if they’re seized. Once the drums are off you need to take all the adjustment out of the adjusters as well as loosening off the handbrake adjustment under the car. Just slacken the handbrake cable, don't loosen it completely. It is unecessary.

After you’ve pulled the drum off the first thing to do is clean everything up. Brake dust, especially on old cars, can contain asbestos. Wear a mask, don’t blow off the dust, do use lots of proprietary brake cleaner. Throw the waste away. You don’t want to re use that rag with now dry asbestos dust on it a few days later!

If the drum is wet inside you either have a leaking wheel cylinder, or you have a leaking half shaft oil seal. Fix that issue before you fit new brake shoes.

This is the sort of thing you’ll find. All that is wrong with this one is that the bottom spring is on the wrong way round.



I pulled off the shoes and replaced the wheel cylinder. The cylinder is held on by 2 7/16th headed bolts, you also need to remove the brake pipe. Make sure the union is free on the brake pipe. If you twist the brake pipe into a spiral it is scrap.




Many years ago I fitted a new brake cylinder that had the seals in back to front. Ever since I check they are correct. Needless to say I’ve never found another cylinder with the seal in wrong! This one, of course, was correct.



The bit people struggle with seems to be the springs. You don’t need spring hooks, pliers, brute force or even ignorance! Note the leading and trailing shoes; you’ll see the brake linings are attached to the shoes eccentrically. When refitting the brake shoes imagine you have a mark inside the brake drum. As the drum turns in the normal forward direction of rotation that mark should first pass over the part of the shoe that has the metal showing.

Firstly put on the handbrake lever, it goes in the central one of the three holes. Put a bit of copper ease on the pin.



Then put on the link rod. It looks like this on the reverse of the shoe. This is the RH side. On the LH side the hook will point down rather than up.



Now hook the two shoes together with the upper spring. Put the fork of the link rod of the second shoe and walk it upwards into its slot. It’ll end up like the photo below. Normally I’d leave the hand brake cable in place but I ran out of hands to hold it and photograph it.



Now put the shoe assembly in place over the wheel cylinder. Leave the bottom of the shoes free from the adjuster. Hook the short hook of the spring into the shoe. The long part is there to give clearance to the handbrake lever.



Hook the other side of the spring in place. You’ll easily pull the shoes over the adjuster against the spring. Make sure the adjuster wedges haven’t dropped out and that the slots are vertical.



Now fit the hold down spring. The spring goes between the two conical washers. The pin goes in from behind, then fit the first washer.



The spring and the second washer then go on. Pulling the handbrake lever up will provide a bit of clearance to fit the hold down that goes behind the lever. (you didn't take it off completely right?) You now have the shoes assembled. This is the RH side of the car BTW. NOTE the leading and trailing shoes!!! I've also popped the anti rattle clip back in blace between the link rod and the spring. Most cars seem to have it missing nowafdays. Its absence doesn't seem to cause any issues.



Put the drum back on the car. Remember the damage potential of the woodruff key! It is VITAL that you fit the woodruff key correctly. If not done right is takes a chunk out of the hub of the drum and new drums are not cheap. The taper of the woodruff key is there because the keyway goes to nothing. The chamfer on the key goes nearest the brake and towards the half shaft.



When the drum goes on don’t push it in too far, have a bit sticking out. The hub nut will push it in.



In the half shaft thread 222 mentioned putting a bit of anti seize on the Morse taper of the shaft. And indeed that is fine on a road car. It’ll be much easier to pull the drum off again. Be careful doing it on something like a rally car. I have been known to lap the drum and half shaft together for a perfect fit. I still have a scar on one finger that I cut along its length when I felt whether the keyway in a drum was OK; I discovered it was as sharp as a razor.

With the drum re fitted it is time to adjust the brakes. If you’ve replaced the wheel cylinders you’ll bleed to bleed the brakes.

Leave the handbrake cable loose. Tighten the adjuster until the brake drum locks. Press the brake pedal a couple of times to centralise the shoes. Back off the adjuster 3 clicks so the drum goes loose. Press the pedal again. And make sure the shoe adjustment stays constant. Once you’re happy the shoes are adjusted correctly adjust the handbrake cable so it will go 6 clicks and no more. You should be good to go now.

Once the car is in use and the free play on the shoes increases as the shoes wear adjust the drums. NEVER use the handbrake adjustment to take up shoe wear.

[Alf ista]

Excellent thread! Thanks a million for sharing this information. I'm am sure some day in the future I will be using it!
Hugh.

[swedishandgerman]

That is the best write up on this forum for a long, long time. Thanks

[redcar]

thanks 940_Turbo,

i'm about to do this tomorrow, so this is exactly what i needed

i'm always nervous around brakes, but looks pretty straight forward now

[940_Turbo]

Originally Posted by redcar

thanks 940_Turbo,

i'm about to do this tomorrow, so this is exactly what i needed

i'm always nervous around brakes, but looks pretty straight forward now

Good luck with it. Let us know how you get on. I've done so many of these over the years it'll be interesting to see if the guide is useable.

[222s]

Originally Posted by 940_Turbo

Ah - that makes sense now!!! Once of mine is definitely on the wrong way round (hooked part outboard), but has a clip to hold the handbrake lever. Can't be bothered to go in there again soon, but will rectify it when I next do.

Whilst on this topic, I've just spent most of today under the car, and also fitting a missing anti-rattle clip (the rattle was really annoying me!!!), only to find that the new adjuster that was fitted less than 2 years ago has lost not only one of the nuts, but also the stud, which appears to be a push fit in the body (pattern adjuster, not genuine Girling). Fortunately I was able to find the old adjusters (OEM Girling), which needed freeing off, due to the old grease being solid, but once cleaned up inside & out, and with fresh copper grease, it did the job very nicely. Very lucky, as I couldn't find them the last time I looked. Has anyone else had this problem with the studs for the adjusters (pattern or Girling)?

[redcar]

well, thanks to this thread and the advice on the other one, got through this pretty quickly today and also changed the rear shocks while i was in there... took about 2 hours and happy days, braking seems pretty good.

this forum is really great for advice and guidance.. keep it up lads

thanks,

G

[swedishandgerman]

@ 940 Turbo - do you mind if I ask the "Forum People" to put this write up under the Articles section for easy reference?

[940_Turbo]

I don't "mind" but personally I don't really like the article section because it is locked. It seems to me part of the value of a forum like this is that people can comment and post up better or quicker ways of doing stuff or ask for clarification if something is unclear. By setting parts in "stone" you lose that.

It may however be that mine is a minority view. If the general view is that it is better off elsewhere I'm OK with that.

[222s]

IMHO what we really need is an FAQs thread* in the articles section or as a sticky, with links to threads like this one. That way the FAQs is kept clean & tidy, but people can comment (as you rightly suggest) in the thread itself.

*IIRC, attempts have been made in the past, but ideally someone who is a regular in this section needs local admin control in order to sort it out.